Because of various travel plans and agendas, it seems that the more options to join in (or opt out) the better. That being said, I realize that Dave doesn't want to have to bring a CPA along to keep track of things. It would be nice to be able to take the boat on Saturday, without having to commit to the bus on Sunday if you have to leave to make it back to work on Monday. Perhaps some form of advance payment to Dave for some options would help him make his minimum commitments.