I'm pretty sure they only serve beer. Last year when I went, a fight broke out between a couple of guys. We told the employee's at the little photography stand who had to run inside a nearby store to call security, which I never did see any come. The security there was pretty bad.
Almost every time I go to Universal with a bag, which isn't often, they usually ask to check all of the pockets, or they at least feel to see if there's anything in them. I think it really all depends on the employee.