I think we need to pay attention to the thread title: No outside food or drink says A Courtyard Marriott.

This is not chain wide, this is just one hotel that decided to establish their own policy, print up their own signs and post them inside their own property.

I would expect this is in result to some staff frustration with the state of the hallways on any given Sunday morning, especially if they happen to host a lot of teenage sports teams, not as a result of some evil policy change at Marriott.

Maybe it's a result of other guests who didn't enjoy stepping over the garbage left by others complaining to the front desk on the way out and saying they wouldn't be back?