Someone happened to post up some coding to insert a tag onto user pages today, thought it would come in handy (especially in helping to tell whether administration is around or not).
I've installed it here and what it does is place a tag on a user's page if they have not edited within the last 3 months. Might be able to edit that, but I think 3 months is good for now, since this wiki is slow and peaceful fo the most part. To see it in action, you can check the founder's page.