"On uk.music.folk somebody suggested a sort of "dead man's handle" device, where the submitter has to respond to a periodic email to confirm that the entry is still valid. No response, entry eventually dies (presumably after a few warnings have been sent and ignored)
Looks like a good idea to me if it can be done automatically.
There will be - there will be an automatic "nag" email, which will just require a click on a link to confirm the event is still extant. This is why I'm keen that people who run events post for themselves, or for sessions say, that they are frequent members who know if the session is still running.