I don’t know for sure if that is why they are asking or not, just a guess on my part since I haven’t been asked to do so. Personally, I feel since all the guests are supposed to be in Disney’s system, they should know the rooms with solo guests. It would be interesting to find out whether the issues are occurring in hotels with interior vs. exterior corridors though. Most of the time when I have been in the room during the check, they have looked in the window first before knocking, so there aren’t any surprises on either side.
I agree the guest should not be forced to leave the room. I would not feel comfortable leaving the room because, unlike when I go to the parks, there is a high likelihood of valuables being in plain sight (i.e., tablet and/or camera in plain sight, wallet out, etc.). So far, holding the door open and remaining in the room has not been an issue. If I were asked to leave, they would have to give me time to secure any valuables and would be welcome to watch me do so through the window, as I would watch them check the room the same way. When I leave the room for the parks, there isn’t anything out in view to be tempting so the fact that I am not present isn’t an issue.