MyVegas One night MGM property requirement

I have purchased a couple buffets that require a one-night stay at an MGM property. I am staying at Mirage for two nights, but checking out Monday morning. The buffets have a Mon-Thurs stipulation, so I'm wondering if i will have troubles fulfilling the one-night stay requirement if i redeem my buffets for Monday after I have checked out. Thoughts? Or do they really check the confirmation number? I will bring the number but will have already left the Mirage.

Thanks in advance.

I thought I only had to show my room key last November. I don't remember providing any proof beyond that. They do a lot of typing on their computer behind the desk/counter, so I'm not sure if they are checking on the system. Just take one of your room keys and give it a shot.

They always ask for my room number when using that coupon, but at the mLife counter when redeeming the voucher. Once it's loaded onto your players card, you should be able to use it any time that day. They do ask you when you'll be going so I assuming it's only good that day. Although, I did redeem a Bellagio Buffet coupon for the next day, which worked fine.