what if they held a protest and nobody was allowed to go?

As noted in the New York Times article “Wall Street Protest Begins, With Demonstrators Blocked”:

For months the protesters had planned to descend on Wall Street on a Saturday and occupy parts of it as an expression of anger over a financial system that they say favors the rich and powerful at the expense of ordinary citizens.
As it turned out, the demonstrators found much of their target off limits on Saturday as the city shut down sections of Wall Street near the New York Stock Exchange and Federal Hall well before their arrival.

I had been only dimly aware of the protest better documented at its home site than I can do justice to. A brief except from their intent I do much agree with:

We need to address the core facts: these corporations, even if they were unable to compete in the electoral arena, would still remain control of society. They would retain economic control, which would allow them to retain political control. Term limits would, again, not solve this, as many in the political class already leave politics to find themselves as part of the corporate elites.

I've yet to see how the members of the protest make sense of what transpired today, but I think they were witness to an archetypal example of that which they are opposed to.

Today was Saturday, on which Wall Street is normally dead of any activity particularly that of the Wall Street Corporations that are the subject of the protest. That is, the people who would have been the target of the protest were at home, probably in New York's various bedroom communities and precisely not present on Wall Street.

And despite a long announced, planned, peaceful protest, with more symbolic content than actual interference, the mayor of the city decided that it would be best to prevent protest in an area where nobody was there to see it. I don't know that the various firms on the street asked that the public thoroughfare be protected by force of police action, but no one can know nor will ever know if they had. It wouldn't be a great surprise if someone chatted with someone who chatted to someone else who suggested that perhaps the right of the people to peaceably assemble be abridged.

Or, if my conjecture is true, the corporations, or more accurately the people who run them, did precisely what caused the protest in the first place: used their corporate weight to have the government serve their interests above those guaranteed to the people by the Constitution.

Whatever may come of this, I do hope that the organizers realize that with this simple act, their opponents affirmatively proved what the protesters allege.