Alright, so normally you get booted out of the game after a certain amount of idle time, with a message saying:
"You have been inactive for some time and will be logged out of the game. If you wish to remain logged in, hit the cancel button."
All you need to do is go to a low level spot, and get some aggro from a mob that hits for less than you regenerate. The mob's attacks will set you in combat, so you can't log out, and will keep resetting the server's timer to kick you off.
Given that no one comes buy and kills your in-game anti-afker, you will have a chat log like this:
Pointless? In most cases. But has been effectively tested to keep you from logging off overnight, during school/work, and any other times you can't be at your computer.
Why do that? Because people who pay for their game time with game cards can cheat their time by staying logged in DAYS past when they normally run out of time. The server won't lock you out of your account until you're actually offline. Of course this will only last until the next server restart/shutdown. But if your card runs out on a Friday and this gives you an extra 3 days to go pick up another card, it's worth a lot.
And don't bother flaming that you get automatically kicked once you run out of game time. It's been tested many times, by myself included, that you can play as long as you want past your game time expiration as long as you and the server are online.