While taking the prep course for the coast guard commercial capt license the
instructors view on the subject was that if a passenger brought aboard a
sandwich or a bottle of pop for you the passenger was paying you for the
boat ride. Or similarly, if you take friends water skiing and share
refreshments they have brought you are being compensated and require a
license because you were "hired" to do the trip.

If I were you I'd get your insurance companies view in writing and proceed
with the trip!

Don Dando