In California you get a free boat ride. Of course, you have to board the boat the night before the trip to check divers in, get everyone to sign waivers, give pre-dive briefings at each site, check divers in and out of the water, make any needed rescues, and anything the crew needs help with. For a single overnight trip you will work from 10-15 hours, all for a free boat ride. If you're lucky they will let you make the last dive of the day. There is no money involved. The tip jar is for the crew only.
The tips do not include the DM? I've never heard of that!