The point is not whether or not the the Piazza is clean afterwards. Of course it is. That is Tower's property. IThe problem is in the surrounding area. I live near New Market and Germantown. I've had people literally pissing on my front steps because they are sort of out of sight. I've seen people leave the Piazza to shit in the lot across the street from me. I saw my street in absolute gridlock for 90 minutes, preventing neighbors from even dropping their kids off while they go look for parking. I've seen an increasing disregard on the part of organizers the further you get from the epicenter of the event.
What I haven't seen is increased police or security during these events.