You’d think the word would be out by now: It’s not OK to carry grenades — or items that look like grenades — in your luggage. That message didn’t reach a Japanese traveler who was arrested last week at the Hilo airport. Transportation Security Administration agents saw what looked like grenades during routine X-ray screening of his carry-on luggage, prompting an evacuation of the terminal area.

Security screenings halted for over an hour while a police bomb squad checked out the grenade lookalikes, determining they were not explosive. The situation earned Akito Fukushima, 41, a trip to jail; he was arrested on suspicion of first-degree terroristic threatening.