You would have to set it up so that you have a unique address for each person for sending to you and they would have to give your their address for returns.

I agree with you...but it can raise negative political implications which could affect your charity overall.

Bad guy gives you money....other good people are influenced not to give you money...

logically it does not make sense...but people are not always logical.

So the answer is?  No?

As an example here is a listed transaction
https://i.imgur.com/SsvOy.jpg

Can't you just send back to the address?  or is that my address?

Why? You can make a unique address for each person sending money. When you give them the unique address get theirs at the same time.

Yes there is. Don't give them your Bitcoin address until they supply you theirs. Then if it's overpaid return some money. You could also in this step have them fill out name etc and keep track of all this in a database on your computer. All money would then be able to go back if needed and you could pick who you are returning it to.

More like bitcoiners discuss bitcoin for nine month straight, trying to look for problems in the system.

It's not safe to refund in that way.

Treat it the same way as receiving "too much" cash in the mail from an anonymous sender.

I'm not a lawyer, so I'm not sure what the legally correct reaction would be in this case.  Destroy the money? Put it in a safe until the situation is clarified? Hand it over to the authorities?    Either way, you can do the electronic equivalent of all those things with Bitcoins too.

What is the problem with doing it like that?

Thanks for the reply.

But, why is that my (as the rejector) problem?
If a donor has sent me some coins, from an address they control in some way, why is that any of my concern if they are using a proxy or not? Surely it is up to the proxy to maintain it's own refund procedures. Once I've returned the money to where it came from the issue is between the donor and the proxy and not me.

Well, if you care about returning the money to the correct person, then you should worry to whom you send it! If you just want to get rid of the coins, feel free to send them to the address in my signature!

There's no guarantee that those in charge of a share wallet can determine that the refund you send was meant for person X. Actually, the address in question could be a deposit address of another person, or just a change address of the bank, anyway, it's impossible to know.