The reply of "it's automatic" won't hold up in a chargeback situation. I would have refused a refund and asked for a voided transaction, but I would still file a dispute. If the issuer wants to eat the cost, I'm fine with that, but it doesn't help solve the problem. This is why we need to be as specific as possible when requesting the proper chargeback codes and specifically the amount by which we were overcharged.

I agree that my phone malfunctions right as I'm about to take a picture. If there is a tick box, I'll make sure I get a photo of that receipt. In places where the quote slip is honored such as Taiwan, Singapore, Thailand, HK (sometimes), Macau (rarely), I'll make sure that the final receipt is free of DCC. At, hotels, I'll make sure to specify the local currency when checking in. It's unfortunate that such a defensive posture is required, but merchants refuse to give a free and clear choice, I'll continue to fight DCC.