I can’t answer your question regarding Disney, however about 7 years ago I booked a couple of Mediterranean MSC cruises through the Italian website while at home in the US. This was back when the US site was just launching so if you searched MSC you would first be brought to the Italian site, then have to select the US site from the main page on the Italian site. I quickly realized that the Italian rates were much less. Obviously the site was in Italian, but I speak a little Italian so it was easy to navigate. Saved me hundreds of dollars on each cruise. Never had any issues at check in. After booking two cruises at two different times something caught on and when I would go to the Italian site it would automatically switch me to the US site. I thought I was clever, never crossed my mind that I could be doing something wrong.