I moderate a system where people will leave for years and eventually come back and reclaim their own account -- sometimes a surprisingly long number of years. We used to delete people for inactivity, but I stopped, because I want people to be able to come back to their own accounts, similar to how you wanted people like Christine to be able to go away to the Peace Corps and be able to come back years later to continue using their old account. Also, on the system I moderate, it's just weird to have someone new start using someone else's username -- it feels like taking over someone else's identity. Also, the system I moderate is set up so that a new person re-using an old username would have author access to the old person's postings, and that could lead to all kinds of undesirable things happening.

So, anyway, what I am saying is that I support not deleting accounts for inactivity!