I consider it important that a good number of votes are needed to auto-delete a node. We are a community, and need a method of group consensus, such as multiple --s, in order to delete.
That said, you may want to leave the power in the hands of those who contribute, but allow all a say. Perhaps a node can only be deleted if it's rep is negative and their are 5 votes in the 'node to be considered'. In other words, it has to be rejected by the community as well as chosen for removal by a group of 'elders' in order to be removed.
Deletion is a weighty matter, something is being destroyed. While it is needed to keep the level of worthwhile matters to static, it must be taken with due diligence.
If a node is up for deletion, it would be good for the author to be /msged and have a chance to reply. Perhaps a node can not be deleted for 24 hours after it is first put up for consideration, with the author (if not Anon. Monk) automatically notified.
As for the matter of Anon. Monk, as they are not established contributers, perhaps those should be easier to delete. Especially because if one was to abuse PM, it would be as Anon. Monk so as not to be down voted. (Or as princepawn, who has the conviction/bullheadedness to say what he wants regardless of who he annoys.)
Also, if there are automatic deletion, what happens to any replies? Are they deleted?
Hope this raises some thoughts.