I agree. Especially if, say, they are being charged by the person - you show up and order your own thing, but they'll still get dinged the extra 15 dollars.
I'm in the Chicago area, and 15 bucks for snacky pub food isn't necessarily all that out of line either.
Asking for money up front isn't rude at all, especially in a group situation. I posted before about the time I paid 30 dollars for an 8.95 plate of food because people stiffed. The organizers, by virtue of being organizers are in the same situation, and properly want to avoid it.
(And splitting a drink bill is a different beast than splitting a food bill. I know that in a pub setting, I typically pay my drinks as they arrive, but food is at the end. Trying to figure out who pays for what in that situation is pretty hard to do, unless _no one_ shared.)