i'd say you don't need them
last weekend i went, and occasionally there were long lines, but they moved fast. so its not like you're waiting in line for hours.
the UE, is actually a waste of money,IMO.
one night we went, there was no lines.
and we also got passes from one of the attendents passing out UE receipts that were to expire the next day.
And, i even had about 40 of the UE receipts after falling on Earthqauke.
[i didn't use them, because i couldn't walk. but, i gave them to a nice family.]
you might get lucky if you go at night. or early in the morning.