Got DCCed twice in Korea recently. Both times I was never presented with the option, the clerk just selected the option on their end of the terminal. Once it was at a Korean restaurant and the staff pretty much spoke no English so I didn't bother trying to get them to void and re-do the transaction.

The second time it happened was at a Starbucks. I should have fought that one because I went there twice. The first time, the clerk allowed me to select the desired currency on the signature pad, but the second time, another clerk preselected DCC without telling me. Didn't realize until the receipt printed.

Other major retailers like Uniqlo, Shinsigae, and E mart all have DCC but they were all compliant and would ask you to select the desired currency on the signature pad.