Just back from the Allure. Didn't see anyone forcing a dress code but most people were dressed nice. Almost everyone wore formal on formal nights. Even on other days, people wore seemingly fresh new clothes at least.
I guess the reason for that was less the dress code but more an opportunity to get good photos.
So basically, yes, it does seem like people keep travelling back to room to change clothes.
Keep in mind though that even though there is a dress code, it doesnt imply that the MDR is an upscale place to eat. The menu is a disaster. You have to practically