LAS VEGAS >> What happens in Vegas … doesn’t stay in Vegas. It is a marketing ploy, people. Really.

Oh sure, you’ve seen the commercials, the ones that say anything goes here. Even the straight-laced are seen smoking cheap cigars and playing slots before they’ve left the airport.

But Prince Harry is not alone. Everyone is fair game, especially when cameras are standard equipment on smartphones and Facebook is just a click away.

Note these examples:

— After a September 2010 concert at the Hard Rock’s Wasted Space nightclub, a bathroom attendant noticed Bruno Mars was taking a long time in a stall — accompanied by a little bag of white powder. A security guard confronted him as he left, and Mars ended up getting probation and community service for a cocaine charge — all as his song “Just the Way You Are” climbed the Billboard charts.

— In 2010, a police officer stopped the car Paris Hilton was riding in after noticing a “vapor trail” of marijuana smoke wafting from the windows. Once inside the Wynn resort on the Strip, Hilton reached in her Chanel purse for lip balm but ended up dropping a small bag of cocaine — right in front of the officer. She told authorities it wasn’t hers and she thought it was gum.

— A group of General Services Administration employees got some unwelcome fame when the goofy skits they prepared for a lavish conference in October 2010 ended up on YouTube. A congressional panel wasn’t as amused by one employee’s ditty about never getting audited by the inspector general. Heads rolled when word got out that the $820,000 event included a taxpayer funded clown, mind-reader, and 24 unassembled bicycles for a team-building exercise.

— Britney Spears walked down the aisle in jeans and a baseball cap in 2004. The pop princess ended up waking up in Vegas next to her childhood friend and decided she should trim that whole “till death do us part” thing to 55 hours of wedded bliss.

— And, last, but not least, Prince Harry, the third in line to the British throne, played a game of strip billiards, only to find that someone leaked blurry photos of the naked royal cozied up to an apparently undressed mystery woman. Prince Harry’s office confirmed Wednesday that the photos were of the prince, but declined to make any further comment.