You no longer control the money once you donate it to an anonymous recipient! You don't get to choose how the money is spent. If you're not comfortable with that, don't put money on a publicly accessible debit card!!
I'm not sure that's the case here. It's not an anonymous recipient, it's Jonathan's stored value card and therefore Jonathan. Jonathan authorized anyone to use his card to buy coffee. He did not authorize anyone to steal his money.
Another way to look at it is as a common fund dedicated to the purpose of buying coffee. Using it for anything else seems like embezzlement.
"I was doing an experiment to find out what would happen if I had a leave a dollar take a dollar jar in an alley, but then some jerk took all the money and ruined the experiment."
1. If the experiment initiator here didn't see something like this coming (someone taking advantage of a free pot of money), he is naive beyond belief.
2. An experiment not turning out how you DESIRE it to does not mean it's "ruined;" to the contrary, it's how learning happens. "Oh, I didn't know that would happen!" takes notes <- Science
