For charity

It troubles me when people do stuff for charity. Not all stuff - i imagine that all sorts of caring, cleaning, and assorted volunteering goes on. But when people charitably undertake to do fun things like abseil down tall buildings, skydive and what have you, then I start to wonder if they're doing it because they want to and the charity thing is to defray the expenses.
Not that the charity minds I suppose, they wouldn't get anything if the fun didn't happen.

But I mind. If I'm persuaded to donate a quid to a worthy cause then that's one thing but I begrudge donating 50p for someone's adrenaline rush.