Many scam schemes are based upon sending some money to the victim and make them forward it. Then the first transaction is reverted and the victim has to take the loss. The concept of the reversibility of transaction can be extended on any purchase: if the buyer can roll back the payment, he gets the good for free.
So the question is: is there a way to be sure that the payment is good and cannot be reverted any more? Something like a confirmation code from the credit institute or a period of time after which any authorization is cleared and nothing can be rolled-back.
To push it a little further, if nothing can prevent a transaction to be rolled-back, someone can found his balance suddenly negative, because one year before he sold the car and the buyer now reverted the payment.
If it makes any difference, I'm asking in the European context.
Related but I'm asking about electronic payments (pay-pal, wire-transfer, credit card, etc...) and not about checks