Undoing anonymous donations All the students in a class are planning to do a trip. Not all of the students can afford it, and it is considered shameful to reveal their poverty. So it is suggested that anyone can donate anonymously to a fund. If the fund becomes big enough to cover the trip, the trip happens. If not, the donators gets their money back, preserving anonymity of who donated and who didn't.
Is this possible?

Yes it is possible if the paiement is done via Paypal / Online paiement.
Bank transactions are validated and done only if the fund limit is reached. So, while the fund is not reached, nobody loose money and everybody stay anonymous.
