Yeah seems OK and people do that yeah. Not everyone, but it is the done thing for many general get togethers. Anyway, don't people bring a bottle out of politeness?
Several years ago a woman I used to know, (ex colleague) saw me in the shopping centre, and invited me and DH to her house to a 'party' for bonfire night. A dozen of her neighbours, and also about 20 family members. were going too.
She asked us on 4th November morning and the party (outside BBQ) was THAT night. She said 'bring some booze and a pack of burgers and some fireworks; everyone is contributing!'
Coz it was 4th November, the only fireworks we could get cost £18, and on top of of burgers and booze, we hardly got any change out of £30! We didn't really know anyone there, the best of the booze was snapped up before we got there, and I don't eat meat, and DH wouldn't eat other peoples BBQ cooked meat. We ended up eating a jacket potato each with cheese and beans, and drinking 2 cans of beers, whilst no-one talked to us all night. Shittiest night ever, and we spent thirty quid on it! 