Finding out if a MUC has been created without Disco

Another question here. For various reasons, it is impractical for me to use disco at this time to find out if a specific MUC has already been created or not. I think I need to know because right now I am having a problem where if I try to join a room (using my bot) that has already been created (or seemingly at least recently created) using the muc.create() call, the behavior is unexpected. The bot will join the room, send it’‘s hello message, and then leave. Problem is, it shouldn’'t be leaving. However, if I join a room that I know has not existed for at least a few days, the behavior is fine.

Suggestions?