they say they didn't and you can't prove it
This scenario ^^ but I can prove it. Now, it will be a point where they won't bother doing a chargeback since it will be so obvious ( actually, the cardholder will see it themselves that is the case ) . I'm assuming it won't stop all chargebacks I was just curious.
But I hear what you are saying D & T.
Most likely you are wrong about proving it. Just about any proof you think you have a scammer has figured out a way around it. You don't have proof, you only think you do and thus will lose the chargeback.