Is it against the rules to log out while your combat clock is still ticking?

Yes. It is against the rules to log out during pvp. On the PvP server, you will basically be dead when you log back in.As for the main, I was told by a mod that it won't let you log out during PvP.

I don't think it can stop you logging out, but I know that on the PVP server, if you log out during combat an NPC appears where you logged out which can be killed and effectively counts as killing you, so it drops all your stuff and when you log back in you get the 'Death' screen!

So it is against the rules in both worlds?

And people can log out while their combat clock is still ticking in the main world. I dont think people physically turning off minecraft can ever be stopped through the server. Ive had this happen to me several times, and have requested the plugin in the pvp world to be implemented in the main world. However, still no answer...

below are two threads related to this problem. The second one was made more than a month ago...

http://www.minetown.net/forum/m/672632/viewthread/3652817-logging-off-while-combat-clock-still-ticking

http://www.minetown.net/forum/m/672632/viewthread/3356411-question-about-logging-off-before-your-combat-clock-runs-down-so-you-wont-get-killed/post/19081853#p19081853