Yeah, it's cool, but also nefarious, charity or not.
Not really... I don't think that the people who put money on the card have any claim to determine how the money is used. It's like giving a gift, once you give it you don't get to control it anymore, and they are giving a gift to an anonymous recipient. If they want to control how the money is spent... perhaps don't put it on a publicly accessible debit card? ;)
I understand that it's not necessarily an unexpected consequence, but that doesn't make it okay.