The Marriott reservation # has been on every confirmation that I've ever seen for a MVC exchange. It's true that II doesn't transmit the MVC status of the exchanger anymore so the resort doesn't have your MVC information. But you do have to look at the 4 page pdf itself and not just the email itself they send when you complete an exchange to see the reservation #. Having the reservation listed in the computer for the destination MVC has never been a problem for us either. The situation I've seen where I would anticipate it being a problem include if the MVC is where the names don't match up such as a name change, hyphenated last name, where someone goes by their middle name or where the lead name on the II account is not the one you are checking in under. II only sends the main name even though they will list 2 names on the confirmation. Also if it's just a day or 2 between confirmation and check in can sometimes be an issue. If you give them the MVC reservation # in those situation it should help them find it. Another thing you can do is to pull it up on the Marriott.com side to see it's in your name which you can do with the MVC reservation #, check in date and name of the main person listed.