This is a good question. I would think a renter should be able to confirm their reservation at the source. Ie. MS.
I know DVC doesn't sanction renting points, but what's to prevent the owner from switiching out the reservation and the renter arriving without a place to stay?
Would the resort have a record of the reservation?
I rented earlier this month and I called MS many times to verify the reservation. I did not mention I was renting, I just stated that I was staying as a guest of a member and provided the Confirmation Number, restort name, and dates of the reservation. MS was always able to confirm the reservation.