My friend and collaborator Matthew Bradley tweeted "The Beck rally is kind of like watching TV, but outside. Lots of camp chairs. Middle area of rally roped off and low crowd density in spots."
It certainly wasn't like that for me, but I was virtually the only one there with a sign. As I was told repeatedly "Glenn said no signs!" I typically responded that they were free to gather and I was free to have my sign. Prompted lots of discussion and debate, some was silly, some was thoughtful; some was rude, some was amazingly gentle.
I'd thought the standard rationale for the no signs policy was right -- organizers are afraid of something vitriolic coming out and causing a stir. But Beck says lots of silly things, so I guess they want to maintain his monopoly.
But I think a deeper reason is that the organizers might not want an outbreak of democracy even within these ranks. They want, as Matthew notes, to simulate the TV experience. They don't want lively discussion among "outsiders" or for that matter among the assembled. You could have an authentic populist movement and not a stage-managed affair.