I've seen those signs in other parks in NYC, but I've never witnessed anyone actually being bothered by the police.

Rivington Street is not exactly "Manhattan's East Side". It is the LOWER East Side, which always was a tough area. This is NOT the "East Village" - it's near that section, but "different". It was, and may still be, considered by many (including some of the biggest entertainment stars in the world) the neighborhood for the best junk in the City (and I don't mean furniture). I took some classes in a training center there in the 1980's and remember it well. I minded my own business and went to my school, but one day a car sped by me really fast, almost hitting me, and turned down Allen St., Eldridge Street, and/or possibly Avenue A. A police car was racing to catch them, and I pointed in the direction that the car went. A guy in the street threatened me for doing this. You never know what's really going on in a neighborhood like that. The rules are different. The only reason I never got mugged, or worse, down there was because the bad guys thought, a) I was a cop, or, b) it wasnâ??t worth the risk that bothering me could bring on some kind of heat. Itâ??s probably not as bad today, but I swore at the time that the entire U.S. army could not persuade the underground culture that thrived there to ever leave. I donâ??t know why that woman was arrested, but I can tell that thereâ??s more to this story than is being reported.