with the recent heavy handed crack down of any NYC protesting, I would be worried of even attempting this. NYC has cracked down hard on freedom of speech.
What on earth would you be worried about? Getting asked to leave? Having to look at a police officer?
If you care about the internet AND/OR you want to show that such tactics don't work, do show up. Otherwise, sit back, relax and get ready for an internet that looks like network television.
Combine that with pointing out that he has admitted he is in favor of censorship and you have the ultimate head-line (especially if somebody brings their kids).
And for protests without permits...the cops are generally going to not do anything but watch unless there's an imminent public safety issue. They don't like bad publicity as much as the next person, and I imagine they're going to be particularly wary of very tech-savvy groups, for obvious reasons.