I've stayed at that property many times and have always had excellent service and excellent Plat recognition. This sounds unusual. I could only see this happening at that property for something really important like:

a) an Americans With Disabilities Act (ADA) requirement, or
b) you extended your original stay and the room was blocked in the middle of your stay because of a request
c) your room is a connecting room to a suite and they sold both rooms
d) your room is a connecting room and the arriving guest is traveling as part of a group where a requirement for connecting rooms is a safety/security issue (ie. traveling with small children)

In all those cases, I would think that the staff at the property should provide you with an explanation and/or an apology and/or a gesture of goodwill.