This is an old thread. It had no followup, and so I guess no one else has had this issue - except me - today. And my situation is just as curious:
1. There is only one admin - me
2. I have a very secure password and run off mac so I really don't think I have a key logger on my Mac. Its the only device I use to admin the site.
3. My server is Unix, which is where the load shedding code can be activated
4. My admin logs are up to date, nothing odd there.
5 My password still works
6 Nothing else has changed, in fact as I did customise the disabled message when I used it (disabled the board for a server move) several months back, the very same text was there.
7. My site is out of date - 3.0.12 so this is not of any current interest to folks I guess, but its curious I think.
My conclusion is that something caused that code to activate that shuts down the board. My son owns the server, and he is 100% sure it was not overloaded or subject to a DDOS attack.