I arrived just before 12:00pm Friday last year, and was parked within spitting distance of the main N/S road that separates regular camping from premier (H2 for those who remember the layout). Pretty much everyone who arrived earlier than I did was parked at least 5-10 minutes walk further out, if not more. I just got lucky from what I understand though. People who arrived when I was setting up my tent were being parked a lot further out judging by the line of cars I saw.
Last year we arrived around 10pm on Thursday and just ignored the yellow shirts and we parked where we wanted to. We were able to get a ton of space along the boundary of the regular camping. It gets chaotic once the sun goes down and if you just ignore the yellow shirts chances are they won't make you stop. It's not like you have anything to lose or anything (they won't kick you out).
The yellow shirts are essentially dealing with a conveyor belt of cars. They have to keep the traffic moving, so if you bitch long enough they'll eventually just give up trying to direct you. Fox's girl managed to get about 6 of our cars all in the same area after the shirts split us all into two groups for absolutely no reason at all.
Did they do the weird overflow in the parking lot last year or was that just for oversoldfest 2010?
I don't think so...we were probably one of the last to arrive (around the time Death from Above was starting) and there was still tons of room behind us in the overflow area/tumor on the side of that picture.