If i go out with regulars they usually chip in either gas or lunch etc. First timers i will not take anything from as we are usually asking them so its just nice to see the enjoyment they get out of it.
Other boaters i will ride with usually its understood there time will come. And respectful friends that have or have had boats that are in between are usually the most understanding as they know the costs involved.
I always deny first but will take small amounts as i don't plan to make money at this at all. I/we would go anyways at my/our expense but a little appreciation does go along way and keeps people on the invite list.