For the record, I do keep a well stocked first aid kit and oxygen (me and wife are both paramedic's) and I do brief guests on the boat/safety very similar to the boat briefing when on a "charter boat". I treat every trip as if it were a charter and maintain a high level of safety, for those reasons already mentioned. Because of my status as a paramedic, and a divemaster, I feel I would be judged againist a higher standard of care due to documented formal training.