I have a feeling the "no anchoring" ruling was borne of noble intentions...
I havent been anchored in New York Harbor or its environs in 25 years, but I do remember the few times we did it (esp during OpSail in '76 when I was just a kid) was that a lot of boats dragged anchor because the Hudson is deep there and most boats simply don't carry enough rode to let out sufficient scope. Today's larger motoryachts are better equipped, perhaps, but the average joe in a 25 foot express cruiser is not gonna realize he cant safely anchor until he gets down there, has a few drinks and then the anchor starts dragging...
My guess is the regulation is meant to discourage all but the biggest die hards from attending, if its not simply a knee-jerk reaction to the anchoring problem.... As for me, I'll be up at the Anchorage playing with sparklers or something...