Another flaw with maintenance mode I found yesterday ...
one of my servers was scheduled for a 5am reboot so maintenance mode was scheduled for 5-6am yesterday.
the server crashed on reboot, never came back up at all. When I got to my terminal at ~8:20am I saw on pulse way dashboard it was offline, but it was still in maintenance mode because the client never came back online to disable maintenance mode. Therefore I got no alert that the serer was offline after 6am like I would've hoped to get.
My suggestion, have clients store maintenance modes on your server against them so it can expire regardless of the client being active, rather then the client itself turning maintenance mode on then back off on your server.