If anyone's still curious about China, here's one more case I bumped into at a Mexican restaurant in Shanghai some time back:

Terminal doesn't obviously indicate a bank on the main screen, just the words "外卡支付". No apparent way to opt out in the beginning, and it does the checkbox thing (it also shows at the bottom that the bank doing the DCC-ing is called "Nanyue Bank" and indicates a mark-up of 3.8%). The cashier has to reconcile it afterwards, but the way to do so isn't immediately obvious; it's a separate process. You have to press 1 to get into the menu, find "DCC退出", then it asks for the trace number on the card slip. Then it runs the transaction again with only local currency displayed, and the slip shows the transaction type as "DCC VOID".