At the Southern Nationals in Atlanta Ga you may stand in line 30 mins. to get to the window and find they only sell tickets for sections A&B and say you want to set in section G. They are not any wall's between the tellers,but if you want section G seats they will tell you what line to go line up in to get them.
That's why I always get mine in advance.
I don't know about out West,but here in the East if you leave your blanket,cooler you won't have either when you return. With a Reserved seat you take everything with you,and when you return you not only have your seat but your stuff as well.