“We don’t want to work if it gets busy. But we still want tips and you better tip more.”
I wouldn’t go that far. Worked in the service industry a long long time ago, and still have friends who do. There is a reason most places have a mandatory 18% or more tip on parties over a certain size, and smart ones also have policies about not allowing to split the bill if the party is over a certain size, and really smart ones, won’t seat a party until EVERYONE has arrived.
I don’t blame them. If I ran a restaurant I’d have the same policies. Large groups are painful to deal with. I absolutely have seen some outrageous thing from large groups in my day. I don’t blame some staff for having negative general opinions of such things.
So the real issue is weak restaurant management, not tardy customers. (Though not allowing separate bills always seems snotty to me.)