As I understand it the rooms are actually assigned before check-in day.
The main thing to remember is requests are just that. Having worked in hotel reservations and seen the tetris game that blocking rooms is (no, not at Disney but at a large convention hotel), I can tell you that the assigners WANT to meet your requests but sometimes they just cannot. And yes, whenever they could not be, people always accused the reservations agent of not listing the request. Bottom line is while there may be some unethical ones who say it just to get you off the phone, the vast majority DO note it - it is just that sometimes there is nothing the assigner can do. They cannot build a whole new room just to meet your requests if one isn't available. Hotels are not cruise ships where everyone is getting on and off at the same time and you can pick your room. Heck, I've even done the "pick your room" thing on the Hilton app and got a text fro the hotel saying they had to change it - and that was within 24 hours!