If you noticed that right as Michelle was about to speak there were about 4 State Troopers who came down to the front center and escorted a couple of jokers away, here they are:
The guy with the "cougar hunters for Palin" shirt on was obviously intoxicated and shouting crude sexual related things to the speakers. He lit a smoke and then when an older lady behind him told him he was being a jerk, he had a few fowl words for her and made a threatening gesture. The lady's husband (assumed) was about to do a little regulating when the troopers stepped in and saved the drunk's life.
The guy in the blue shirt and tie standing next to him was provoking the audience as well but he was far less obnoxious.
That death panel sign was my favorite!
It was hard for me to judge the crowd size from where I was standing but I will agree with your 4K+ number. Channel 4 had a camera crew up front and was interviewing a few people so it will maybe make the news tonight.