Just a wild idea, which I hope will stimulate your creative juices.

Have you considered running sp_who, at least it will tell if some one is using the database, if no one, can you then do your fix up task with an exclusive lock on the table in question?

My wild idea, schedule a job to run sp_who say every 30 minutes and insert the results into a temp table, query the temp table, if the database name is not found, then do the fixing up.