Just stayed in June 2018 at Park MGM and got one $25 free, one $50 Free play, and one $100 free play. They were all loaded on to my mlife card after redeeming at mlife desk. My room were free for all 3 nights through mlife comp. So it does not appear that the restriction is enforced. My brother in law also redeemed his under his own mlife claiming he's staying at Park MGM in my room. The Mlife host just went and added the credit to his Mlife card. I'm going back in a week and will redeem the same amount for all three free plays from MyVegas. Will let you know if they still work. The only restriction is that in between claiming these free play, you cannot purchase more within the 90 days period.