Usually when a group grows to a certain size, somebody will decide that rather than chipping in $30, because they "just had a salad", they'll toss in $12.95 for the salad, skip tax and tip and disappear.
Interesting. In Poland, and most EU places I've been to, the prices in restaurants and stores are almost universally gross, to make it easier for the buyer to know how much they'll pay.
I think how it goes is you collect the money. The other diners include tips and tend to round up. You take their tips and use it to pay your own bill. The waiter/restaurant lose their tips, your friends lose face and are tricked out of they're generosity, you get food for no money.
Usually when a group grows to a certain size, somebody will decide that rather than chipping in $30, because they "just had a salad", they'll toss in $12.95 for the salad, skip tax and tip and disappear.