The school has already said that they will not allow the show to be hosted because of the damage done to the grass.
Although the city cannot prevent people from staying in OC, they can make your life hell by pulling people over for very small things. They will harass to the point where people will give up on that weekend and not bother.
Take a look at last year's blotter which is on their site. They set a record for tickets issued. If the the city can't kick us out, they will harass us out. :p