30 mins is to long they can sit in vd1 for that amount of time. I mean that if you dont move or anything for 5-10mins it will give you a random code. If you get the code wrong or dont answer it logs you out.
Yes i understand you but i agree to what said ArabianArrow too :
Macros can be made so the person moves back and forth, and repeats. The 5 minute rule is bad for obvious reasons >.<.
Its really easy to make it ... and even make your character attack in the same time ... only solution for that would be the anti-hack system that GMs worked on and :
They're making monsters have random spawns (don't know if its all), so you can't line without the risk of dying.
So imo when the GMs anti-hack tool will fail then this is an
additional anti afk/hack system
only when it pops out
always (if it pops out only when afk ... its only anti afk) :
Saw it already in some mmos (for example Angels Online

)... it does a great job as one of the anti afk systems ^^ .. but 5 min is too often anyway... i would say it has to be random between 15-30min(or even longer) cause it will get annoying to write code every 5min when you are in battle (pve or pvp).... oh and 1 more thing ... you have 3min to write the code , if you dont then you get some kind of penality(in case of Angels Online its going to jail but here i think it has to be something else because you just could relog in that case) ;
-your account banned for 1 day
-only disconnected
-something else ;p