I keep going back to the situation in the OP. If you are only paying $300, then YOU don't have any RIGHT to be insulted. Because you are a jerk for ever even trying to get a full band to set up in your yard and play a four hour gig for $300. Had I been the OP, not only would I have laughed at him when he "announced" such a ridiculous gig, but I would have personally CALLED the ridiculous idiots ("hosts" as you call them) and told them where they could stick THEIR $300.
Certainly nobody here is saying that setting out a tip jar at a formal party where the band brings down $3500 (which is the LEAST I will do a private party for) is a good idea.
But in the situation that started this conversation, there was obviously nothing FORMAL about an event where the "hosts" only wanted to spend $300. Nothing classy. Nothing formal. No rules. It was a backyard jam. They should get what they PAID for. And they did NOT PAY FOR a formal band setting. They got a buddy to do a favor. NO RULES apply to this ridiculously cheap "event". Period. None whatsoever. In fact, these "hosts" were not even CUSTOMERS in my view. $300 may as well be a sandwich and a few beers. It is worth about the same. The guy who BOOKED the gig should have been insulted and slapped the "host" across the mouth. The BAND should have thrown the guy who BOOKED the gig into the nearest river.
As for kicking my tip jar...... If you were rich, and tried to get me to play your backyard party for $300, I would personally hang up the phone, drive to your house, and shove my tip jar up your.........