I believe (but am not sure) that the buyer can cancel F & F, but I know for a fact that they could purposely drain the bank account after the transaction is approved initially. They could also claim that a credit card transaction was unauthorized. In the first case, seller is screwed because there's no backup funding source for F & F, so the transaction simply gets cancelled and charged back to your account. In the second case, if the CC decides that the transaction was unauthorized, PayPal won't help you no matter what the underlying facts of the dispute are and seller is screwed. Also, I don't believe sellers have any way of knowing what the funding source was on the buyer's end (without simply taking the buyer's word for it). The safest bet might be to use F & F but wait to send the item until your bank confirms that the funds have actually been collected from the buyer's bank, rather than just "posting" to your account.