Gotta disagree. Tilly is one perlmonks' most prolific posters, yet he disappears from time to time. As I understand it, his work sometimes requires that he refrain from posting on public forums, so there are long periods of silence. Had we enforced a "three months of silence" rule, Tilly would have been nuked and we would have lost one of perlmonks' most valuable resources.
Furthermore, if a user is nuked and the namespace freed, how do we label the previous name-user's nodes in order to distinguish new-Tilly from old-Tilly?
"What do I want? I'm an American. I want more."
Ughh, I do not mean three month of silence, I mean three month for the first post. If there is a post the user can silently watch the rest of his live.
It is just to clean up users that register and do nothing then.