sending the money back wouldn't cost any fees. Also I haven't accepted the money yet, so there aren't any fees to pay.
But if I would accept the money we would have to pay fees.
I have to accept the money to update the widget.
My solution would be a official maemo.org developers fund (paypal account) where everyone can donate.
Donations don't need to pay the fee.
It seems, that the chipIn page transfers the money as payments and not as donations.