where you get this from? There is no rule saying you must respond to anyone in game, so there would be no possible way to see if your "at the keyboard" Just wondering where you read it or if just pulling it from the bum?
Read the Rules of Conduct, specifically section 1.1 number 6.
GMs are given extremely liberal interpretation rights. If you're running AFK with mercs, and someone comes into the area to hunt the mobs you're killing while AFK, they can, what used to be called, 'PnP you'. If you are not there to respond, do you think the GM will just say 'Oh, no one's there. You'll have to move on, PnPer'? Some GMs might, I'd say most wouldn't.
And before you say GMs wouldn't even intervene, there's a magic phrase that is often used (or was used last week by someone I'm familiar with): I need these mobs for a quest. After 45 mins, the AFKer was booted from the server and the guy took over the camp (with heavy MQ2 use).
Also, your "There is no rule saying you must respond to anyone in game" assertion is, at best, half right. Again, rules of conduct, this time #7:
7. You will follow the instructions of authorized personnel while in EverQuest or on the Official EverQuest Forums.
Thus, if a GM ingame tells you to do something and you do not respond, they're allowed to take action against you (via your account). That's always how I've always understood it. Granted, I haven't personally known a GM since Saviente and Chrol left (and my short stint as a guide made me want to literally kill Michelle Butler...though years later, I got a kick out of the antics that occurred at Sigil that left her devastated) but that was my understanding.