If someone in a position of authority rounds up “the team” and says “we're going to lunch” it really isn't optional, you just go. Even if you brought in lunch, you just go.
So today, this happened to me and at the end of lunch, she has the waiter split up the check. This wasn't a cheap place either. She took nearly two hours of my day (my overtime, technically... that's money right out of my pocket) and had the nerve to expect us all to go dutch too?!?
It's rude of me to say “who's paying?” the next time she asks, but my time and money are very important to me. I guess the other options is to politely decline and make some lame-ass excuse about being short on funds.
It sucks because I shouldn't have to make this decision in the first place. If you're in charge of a team and you insist on removing them from the workplace for more than a typical lunch duration (without the apparent option to decline), at least have the decency to cover the bill.