This happened to me in the Sheraton on the Park in Sydney, when I was a "well educated" Business traverler. I just happened to look at the exchange rates, as was under US perdiem and it was more than the daly rate alloted. I asked him to convert to AUD, and saved about 12 USD on a 1 night stay. They clerk didn't want to do it because "you are getting a better rate when we show it to you in dollars". I didn't know what DCC (thought it was limited to my forex experiences) was until today though, will be looking out for it on future travels.