Anyone who's ever been screwed by PayPal or the like has plenty of reason to support the irreversibility of transfers. That's not to say that there should not be a way to recoup losses, but the fact that a third party can just pull money out of your account, pecunia ex machina, goes way too far in the other direction. And no, the reams of incomprehensible legalese that supposedly justify this are not good enough.