Originally Posted by
LongingForORD
They told me once I check in on line, they can not change, move or re-assign the room.
Whilst I don't doubt that is (at least their) policy, they definitely can physically do it.
Twice in different hotels I've been the cause of people being moved from the room they had already checked in for. One was me deciding to stay for another night where someone had already checked into my room for the next day, and the other was an early arrival where they had upgraded me to a suite but it wasn't ready, so they swapped me with someone else in an equivalent room who had already checked in.
I remember both occasions simply because in both cases they stated someone had already checked in, and it took some additional effort to move them.
Both of these were well before checkin time, and from memory both in hotels without digital keys (one definitely doesn't, not 100% sure about the other). Not sure if that's relevant, but it would mean they know the person that's checked online in hasn't actually accessed the room yet.