The more I hear the more I think there should be a tip sharing jar with a slot, to be opened only by owner/manager. I work as a DM on a weekend liveaboard once or twice a month and we put out a basket at the end and tips are shared equally. This results in us giving our best service to everyone because we don't know who will tip well or not. I've had people offer me cash and the automatic response is thank you, please put it in the basket.