There is a reason Amsterdam insists on placing those red lights in the hooker district: to alert passers-by that there's some sexin' going on in the hood. But New York City employs no so colored devices — though perhaps it should. At least along the High Line.

The recently opened renovated+elevated park that's given New Yorkers reason to believe they don't live on an island clogged with pollution and garbage is also the surest way to sneak a look at exhibitionist tourists. Anyone staying at André Balazs' The Standard who keeps the windows open while getting it on is also giving a free show to High Line visitors and surrounding businesses. And some are less than thrilled about being privy to porn shorts and solo j/o shows.

Disgusted neighbors say they've seen men masturbating, professional porn films being shot and couples engaging in sex in full view of the stunning High Line park path running alongside.

"That crazy kind of behavior is completely unnecessary," complained Bobby Shoule, 37, of Queens, the father of a 15-month-old daughter.

Business neighbors also are disgusted.

"I've seen a few porn shoots — three dudes walking around a hotel room with cameras and lights filming a couple," said Joe, a manager at the next-door Brass Monkey. "I've seen at least 10 different people having sex. Saturday nights are the best time for the show."

Except what do you expect from a hotel that launched last year with these ads promoting it, and a Facebook page that — until a reporter called with questions — told patrons: "We encourage you to exercise your inner exhibitionist. Please share your intimate, and explicit photos with us — those floor to ceiling windows aren't just for the views." (The Standard website asked: "Whatever you do, just make sure the shots are HOT and that you get them to us in whichever way you can. It's all about sex all the time, and you're our star.")

(Thanks, Cam!)