If the traffic to PayPal confirming the transaction wasn't from a centralised server, PayPal would have no way of differentiating between an ETH sale or any oth

If the traffic to PayPal confirming the transaction wasn't from a centralised server, PayPal would have no way of differentiating between an ETH sale or any other transaction, so their cooperation might not be needed. Reversal - might be better solutions but couldn't the smart contract escrow simply have a timer built in that would allow the fiat receiver to move the money out of his PayPal account, thus preventing reversal? I'm just running with a half-baked idea, but it feels like it could work. Doesn't need to be PayPal, could be any fiat transaction provider that has an API that allows confirmation of the fiat transfer that the smart contract can access