Originally Posted by
DallasEsq
What I would do is book the first night or two through MGM, and the rest through Marriott. Maybe they will give you an upgrade initially and then just let you keep the room so they don't have to clean two to make you switch. I don't know if that would work but that's what I would try to do.
I've done this before although under Hyatt/MGM. Booked a night award through Hyatt and then had MGM booked stays immediately after. The front desk will let you stay in the same room without any problems.
Even for longer stays (2 wks+), the front desk will sometimes ask if you'd like to change rooms to have a different view and not get bored of being in the same place. So it really depends on who you get and in my experience, if you're nice about it.