I just scored 1850+ on Mahjong, way above anything I've done before, but TCS booted me out during the game so my score wasn't recorded! I'm so disappointed.
I've been logged out involuntarily waaay too often playing that AirTyper game. What I do to combat it is to have two windows opened. One of TCS Game window, and the other on any other TCS page. Every now and then I would refresh the other page, so it shows that my account is still on an "active" session and doesn't boot me out.
As far as I know, the arcade itself, or rather the games, do not log you out. It's possible that your set up to be logged out of TCS after a certain time of what the system sees as inactivity. When you play a game, that's considered inactivity, because in effect, the game file is downloaded to your computer and doesn't run on our server.
It's a cookie issue, essentially. What happens if you just leave a TCS window open for the same duration of time, without posting or viewing threads? Does it also log you out?