My experiences of being denied late check-out has only been recent too so i do wonder if there's an internal memo. But never had a problem with it on previous years especially at legacy Starwood Properties.
But now whenever I need late check-out I email the property in advanced, and if they say it is not guaranted, I cancel.
2 properties wouldn't confirm my request through email last month, Moxy Frankfurt Airport Kelsterbach & Villa Rothschild Autograph Collection Frankfurt.
I also got an email from Villa Rothschild Frankfurt stating that they cannot guarantee my 3 or 4pm request but i must have deleted it after I canceled my reservation with them.