Maybe that's the problem -- don't wait to be "given" the late check-out, just take it! It's your entitlement except apparently at certain resort properties.
So I go under the assumption that the front desk knows I will take the late check-out since it is my published benefit as Gold, and I expect them to proactively tell me if for some reason I can't do it. (Though even if I still did, not sure what they could do - escort me out of the room? charge me extra for my free benefit?)

I've never had a problem.