Mika Salamanca’s mug shot is a departure from most of the images you’ll find of her online, particularly the ones she posts on Instagram to her 1 million-plus followers — winsome selfies and playful portraits with her head cocked to the side. But in the photograph released by the Honolulu Police Department, Salamanca, a social media influencer from the Philippines, stares directly into the camera, her expression inscrutable.

Salamanca was arrested in Honolulu on July 24 for having broken the state’s mandatory 14-day quarantine. She was apprehended after posting images and videos out with friends within days of her arrival, leading a group of locals to report her to authorities.

“One day it will all make sense,” reads an Instagram post from Aug. 4, which racked up more than 33,000 likes.

Whether it makes sense or not, Salamanca’s transgressions, subsequent arrest and public apology is one of the more titillating, and public, examples of quarantine enforcement in the United States. But as quarantine requirements for travelers have become increasingly common throughout the United States, in states including New York, Vermont and Kentucky, plus the city of Chicago, the prevailing theme is the difficulty of effective enforcement.

Roughly six months into the coronavirus pandemic, local and state governments have struggled to contain the spread of the coronavirus with limited manpower and dwindling resources, and following quarantine rules is more often than not left to the traveler’s discretion. Officials hope that threats of fines or imprisonment and, more crucially, an honor code state of mind, will prove effective. But as issues of right and wrong become increasingly muddied in our ever-shifting pandemic world, can travelers be counted on to do the right thing?

Hawaii’s quarantine order for trans-Pacific travelers went into effect March 26, and currently applies to everyone who enters the state (Gov. David Ige further instituted a partial quarantine requirement for inter-island travel, beginning Aug. 11). Those caught breaking quarantine can be fined up to $5,000, or imprisoned for up to one year.

In contrast, most other states’ quarantine orders are only required for travelers coming from places experiencing high infection rates. In New York, that currently includes more than 30 states, plus Puerto Rico and the U.S. Virgin Islands, according to a list that is updated weekly. Those who violate the quarantine order are subject to fines up to $10,000. Connecticut has started issuing $1,000 fines to visitors who fail to submit a travel advisory form to its public health department or violate quarantine orders. Other states, including Ohio and New Hampshire, frame quarantine requirements as recommendations or requests without the threat of fines.

Hawaii’s geographic remoteness, and the fact that it is, well, a group of islands, puts it at an advantage when it comes to monitoring who is coming or going. All travelers are required to fill out a form provided by the state’s transportation department upon arrival, and quarantine enforcement is handled by individual counties. As of Aug. 11, the state reported 27 arrests on Oahu, 22 in Maui County, 29 on the Big Island and 60 on Kauai, according to Krishna Jayaram, special assistant to the state attorney general.

“This program, like everything with COVID, is something of a learning process,” said Jayaram. “If we’ve become aware of someone who may be violating the order, we conduct a pretty thorough investigation.”

Many investigations are spurred by concerned citizens, some of whom are banding together on social media to root out quarantine violators. Hawai’i Quarantine Kapu Breakers, who alerted the authorities to Salamanca’s transgressions, write that their purpose is, “to bring awareness to issues surrounding tourists and locals not adhering to public safety standards during the pandemic.” (Salamanca did not respond to requests for comment.) Incidents of community policing have also been reported in Florida, South Carolina and Kentucky, plus examples of particularly vigilant enforcement against Americans attempting to sneak into Canada.

Quarantine violations seem particularly egregious in Hawaii, where, comparatively, the rules are unambiguous. Brad Johnson, who lives in Maui, traveled to Kentucky in early June to be with his ailing father. Johnson noted that, upon returning to Hawaii weeks later, it was virtually impossible to exit the airport without filling out a form and interacting with government officials, including the Hawaii National Guard. He was required to provide his phone number and told to turn on his location services. Still, he noticed that a number of people who had been on his flight were pushing back both in transit and upon arrival.

“There were maybe a dozen people who were not wearing masks, and kind of creating a ruckus,” he said. “I saw one of these women arguing with officials, and refusing to turn on her phone’s tracking. She was visiting family; it was her right, they were violating it. The officials made clear that her other option was to get back on the plane and go back.”

Johnson was contacted twice by government officials to make sure that he was abiding by the rules. Other states, in contrast, are making enforcement a much lower priority. Furthermore, the rules of what is and isn’t allowed are less clear.

New York also requires visitors from its changing list of hot-spot states to fill out a form sharing their location and contact information. But the threat of enforcement remains lower than that of Hawaii, not least because of the sheer number of visitors and the disparate entry points. Since the first quarantine order was issued June 25, the state’s health department has worked in partnership with the Port Authority of New York and New Jersey to ensure that health officials are stationed at airports and positioned by flights arriving from applicable states to hand out and collect forms (those who refuse are subject to a $2,000 fine).

On Aug. 5, Mayor Bill de Blasio announced plans to set up checkpoints on metro-area bridges and tunnels, plus similar setups at Penn Station and the Port Authority Bus Terminal. But details of the plan were scarce, and somewhat confusing. According to Amanda Kwan, a senior public information officer at the Port Authority, “The Port Authority has been in contact with the city, and their effort will have no operational impact to any of our facilities. All vehicle checkpoints are being set up off of Port Authority property without Port Authority personnel.” As of Aug. 14, the majority of stops made were on Staten Island, while only 36 vehicles entering Manhattan were stopped.

Bethany Mitchell returned home to New York on July 14 from San Francisco, having left the city in March to stay with her boyfriend when her work as a performer with the Battery Dance company dried up. She wanted to try her best to follow the quarantine rules, but found some of the asks unclear, or unfeasible.

“I hadn’t been in my apartment for four months. I had to go to the grocery store and pharmacy; to do things to function,” she said. She looked into delivery options for her groceries, but found that it was prohibitively expensive. She also got tested shortly after arriving; when she got her results a week later, she began seeing friends from a distance in parks. “My mindset was, ‘At least I didn’t bring it from California!’”

According to Gov. Andrew Cuomo’s office, a negative coronavirus test is not a pass from quarantine, but this information can be hard to find (it’s on page six of an online FAQ). And for a number of states, including Vermont and Alaska, a negative test can be a quarantine pass. In lieu of clear guidelines and regular check-ins, Mitchell said that she made choices that felt safe, financially viable and rational to her (she was contacted by the state health department once, on day 13 of her quarantine period). The governor’s office could not share numbers of those caught violating quarantine in New York.

The desire to do what’s right is common, but defining that is difficult as people receive mixed messages. Dr. Erez Yoeli, a research scientist at MIT’s Sloan School of Management and director of the Applied Cooperation Team, said that the lack of consistency in the rules on the national, state and even city level leads to ambiguity, which leaves room for plausible deniability.

“That makes it hard to make these rules social norms,” he said. “Without those social norms, there’s no way that society can enforce the rules informally.”

Still, “soft” enforcement remains central to many of these quarantine plans. Dr. Allison Arwady, commissioner of Chicago’s public health department, said at a recent news conference, “Our primary objective is about educating and informing the public.” Chicago is currently requiring a two-week quarantine from 19 states and Puerto Rico. Arwady noted that, while the city does have the ability to issue fines of $100 to $500 per day, enforcement is not her main goal. “I have absolutely no intention of pulling cars over that have out-of-state license plates, (or) developing watch lists of people flying through the airports.”

This leaves some businesses in a challenging position. Hotels, for instance, can receive guest reservations from a variety of sources — online platforms like Expedia, travel agents, direct booking on their websites — that provide varying degrees of data and information about where a guest is coming from and if they would be required to quarantine.

“When it comes from our website, we can get more information from people,” said Robert Baum, a partner at Bedderman Lodging, a hotel group based in Chicago. “But even then we have a better shot of knowing where they live, rather than where they were most recently.”

Baum said he has reached out to the city for advice on how to deal with guests. In the meantime, Bedderman is emailing all guests coming to its three hotels to inform them of the city’s rules, and further reminding them during the check-in process. Again, the hotels aren’t necessarily able to track whether or not guests are coming from hot spot states; they aren’t checking passports or parsing credit card statements.

“Unlike other retail businesses, it’s pretty much a guarantee that people are coming in from other places,” Baum said. “It puts our staff in a challenging position. When there’s no real way for us to police these quarantine rules, it’s hard for us to reassure them.”