I had a team that was partially sponsored by a local proprietor. We had no agreement in place regarding payback.
I felt I knew the gentleman well enough to ask. So I did. We cashed for exactly the amount he kicked in, so he asked us to split it with him, which we did. The team went along with it. If we'd won more than double what he kicked in, he would have only asked for his fees to be paid back. His way of looking at it was - you guys bowled, you did ok. This way the money will be in the pot to do it again next year.
I thought it was reasonable, since he was never asking for more than his original investment. That evens out completely - if I'd paid it myself, I would be keeping it.
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Bowlers are like puppies. The only difference is that someday the puppy will quit whining.
-- Found at Sam's Town Pro Shop