I recently booked a few hotels for my trip to Europe later this year and opted to pre-pay a couple of them as the rates were cheaper. I received my credit card statement this week, and noticed that one of the charges appears to have been processed using DCC as the charge showed up as a single line item in my home currency. The other was processed by the credit card firm and the currency exchange rate was shown. I haven't yet analyzed the charges to see what the difference was in the exchange rates but will try to do that in the next day or so.
I don't recall being offered a choice in how the charge would be processed when I booked the rooms, but I'll certainly be watching for that in future.