I have noticed that when a show gets deleted from one machine the other recorded TV machines still have the show in its inventory. I suppose i might not have things setup properly, but if not it should be a feature. I think a central database might help solve this one.
The file watchers on each system are supposed to catch deleted items but if they don't they should sync up within a few minutes (5 minutes at most).
There are some things that I would like to have a central database (or a synchronized database) for, but there would be a lot of reprogramming that would have to be done... At this point I have a lot other things I am working on, but it is on the list... jut not really sure how I would implement it yet.