BY 11, sure. Not necessarily AT 11. So it's entirely reasonable that not all rooms can be available at exactly 3 PM, and if you read Bullseye's experience, you'll even see that the actual - not printed - policy is, indeed, after 3 PM. And no, that's NOT restricted to Walt Disney World resorts.
Right. If you watch, the cleaning crew starts early in the morning and goes throughout the day - again, this is a statistical game - they COUNT on an average number of people leaving early so the crew can get the rooms cleaned early, and then have more crew coming as 11 nears.
The unavailability of a room could be due to any number of causes:
1. The unexpected extension of some stays
2. The unexpected late checkouts of some guests
3. The unexpected removal of some rooms from availability (like the guest ruins the room)
4. The unexpected (yes) overbooking of the hotel
5. The unexpected early arrival of guests checking in.
It works just like a restaurant - I make a reservation but don't have a particular table set aside. If EVERYONE seated before stays in their seats for 2x the normal time, guess what, maybe I don't get my reservation. It happens. While disappointing, there isn't an expectation that the place would set up a table in the hallway - or kick out a prior diner. It just happens.
I think there are two ways to minimize the risk from a consumer standpoint:
1. Book with a frequent guest pass, or through a
travel agent, or through your company. Do what you can to show that your stay is tied to more than just a "one night stand"
2. Arrive early, even before check-in time. You probably won't have a room ready, but you;ll be on the "list" of people who are now in the lobby and you'll more likely get a room.
Translated - I'm always most worried when I book alone and show up fairly late in the day.