There must be something in the water at the hostels in Cambodia.

For the third time this year, a group of tourists has been arrested at the Angkor Archaeological Park for taking photos in the buff.

It’s a bizarre epidemic of — ahem — “overexposure” at the centuries-old UNESCO World Heritage Site, most famous for the Angkor Wat temple. The trend has gotten so bad that the Apsara Authority, which manages the temples at the site, had to put up flyers warning tourists that nude photos “desecrate” the sacred site — just in case it wasn’t clear that stripping in a temple might be considered inappropriate.

Officials there are offended and more than a little fed up.

“Our park was built to serve religious beliefs, so showing naked bodies is not acceptable,” Apsara Deputy Director Long Kosal told the Cambodia Daily.

According to Kosal, two male tourists were spotted with their pants down Sunday afternoon while a woman took their picture. The authority’s tourist guards interrupted the “photo shoot of their buttocks,” as Kosal described it, and arrested the three foreigners.

A local prosecutor told the Daily that the court has not decided whether to summarily try the tourists or send the case to an investigating judge.

In similar cases — a group of three French men in January and a pair of American sisters a month later — the offenders have been fined and deported. The Americans were given a four-year ban on returning to the country. A fourth incident involving nude photos of a topless woman that were circulated on Facebook was condemned but never prosecuted.

“This is the first time we’ve had to deal with several situations like this in such a short time,” Apsara Authority spokeswoman Kerya Chau Sun told the Phnom Phen Post in February, after the initial three incidents. “I don’t understand what would drive people to do this.”

Alison Carter, an archaeologist who studies the site, chalks it up to ignorance.

“I think tourists frequently forget that the Angkor Archeological Park is not an amusement park, but a place with living communities and many sacred places that are still actively maintained and worshiped,” she told CNN.

But Angkor isn’t the only World Heritage Site plagued by nude visitors. Authorities at Machu Picchu dealt with a similar epidemic last year, arresting eight people for streaking in a single week.

Their comments on the issue sound like a parent chastising an unruly toddler.

“There are places in the world that people can get naked,” Alfredo Mormontoy Atayupanqui, director of archaeological resources for Peru’s Ministry of Culture, told CNN. “But not all places are (appropriate) for getting undressed,” a 15-century Incan citadel among them.

It’s not clear what’s driving tourists to take their clothes off at temples. Aside from a now-defunct twitter account called “NakedAtMonuments” and an Israeli man’s blog called “My Naked Trip” (warning: both are, predictably, not safe for work), the trend doesn’t quite qualify as a meme. Besides, there have to be easier ways to become Internet famous than getting yourself fined, deported and banned from a country.

Chau Sun of the Apsara Authority told the Phnom Phen Post she’s not much interested in the reason for the photos. She just wants them to stop.

“Whatever it is, it’s disrespectful,” she said.