I often 'idle' for a good amount of time, but not what I'd consider excessive amounts of time (2+ hours.) I say idle with hesitation, though, because while I am
technically idle as far as the MOO is concerned, I'm almost always present at the keyboard and actively monitoring what's what in the game world. That's where I draw the distinction, personally, between idle and away as statuses- not that it's something codedly possible to derive.
I suspect some others are as well, but to what extent this is true, I have no idea. I've never been a fan of idle timers, as you stated Slither, and I'd probably be one of the people getting annoyed by getting disconnected during writing work emails or being in a conference call. I understand these timers, but I think a lot of the commonly-raised concerns in the world of idle timers (things such as blocking server queues up, wasting bandwidth in realtime games, achievement/epeen farming, etc don't really apply to SD or MU* in general.
I get where Hek is coming from, in saying that people are just going to game the system. I won't even make the claim that they'll use rules-breaking methods, but rather just whacking the look command or something every thirty minutes or whenever the fancy strikes, and never having this idle system trigger.
What I don't understand is why make code changes for what seems like a pretty straightforward and easy-to-ID rules infraction? If JoeStaffer runs a @who and sees someone's idle X hours, shouldn't the policy be to just @boot/disconnect them and leave an internal note that the player was found to be idling? I guess code would be a staff QOL update on this, but it just seems like more timer/tick based overhead for the server to track and manage for what I assume is probably only a handful of people regularly 'abusing' this.
Just my two chyen.