I've said it before and I'll say it again.
Until real time, hotel equivalent of airline "seat maps" are available to guests, FD Agents & Management can lie all they want about what they have and what they don't or are unwilling to give away. They have no way of being caught in the lie except for you getting up at 5 AM and noting where the newspapers are!
I don't know what it is, but a huge percentage just don't want to be cooperative and accommodative beyond what has been pre-blocked before you arrive.
And I'm not just referring to Suite and CL upgrades, often its simple requests like away from elevators, down the hall away from neighbors, away from the parking lot, etc. in obvious dead weeks (like I made before going PLT).
I'm always convenienced that the Standard Operating Procedure is to pre-block people together serially and it becomes a FD effort to undo that now matter what your status or requests. After all, it makes it easier for housekeeping.
Just my experience, certainly not all locations nor limited to Marriott.
Two weeks ago, I was denied a 2hr late checkout at a RI on the Sunday after Thanksgiving. I was hoping that my 2 boys could shower after their hockey game before a 5 hour car ride home. "A large group" was coming in that night the FD Agents were trained to say.
Sure, someone is having a large meeting that requires travel on the 2nd busiest night of the year??? In reality, the hotel wanted its housekeepers to finish up and go home ASAP.
Again, its much easier to lie when you can't easily be caught!