Originally Posted by
Kacee
Marriott's reservation system doesn't catch duplicate bookings, so the reservation will be fine. I doubt it will impact on property elite benefits, either. But you won't get credit for two stays on the same night.
While this might be true in practice, there are risks. A colleague of mine had concurrent stays at two different properties and was given Platinum benefits at both. A few weeks later, he received an email from Marriott basically saying they noticed and if he did it again, it could be grounds for terminating his membership. I don't know if he was just the unlucky subject of a random audit, but it shows that gaming the system isn't without risks.