I'd like to make a suggestion that when a topic gets moved, any subscriptions to it get cancelled. After I just archived many topics, it took me quite a while to cancel all the subscriptions for the now permanently-closed topics. I just think this could be a useful part of the archive tool.
We had a discussion on this during development. Particularly when a members account is locked or deleted that the subscriptions are removed also. I thought we had addressed the subscriptions too when topics were archived.