As far as I know room scripts are (like MPI property-based scripts but unlike MUF programs) considered part of a room and therefore ownership is transferred with the room. On the other hand, I don’t think there is any special access granted to your character beyond being present in the room (i.e. it can’t mess with your character description just because you own it).
To the wider question: it would be a nice idea and as previously raised it’d also make sense for other characters on your account to be able to modify your rooms/scripts, even though the room officially belongs to the character rather than the account (after all, the room limit belongs to the account).