Meh, I don't consider AFK much different than watching a movie while exploring. The mechanics are there in game to do it, chaff hinders the turrets but eventually you'll kill the little buggers. The only problem I could see would be getting a friendly fire incident accidentally, but not sure turrets would do that since I haven't used them since before engineering. I've never seen a situation where bad guys are constant though, even in CNBs they seem to fade after awhile, maybe I don't wait long enough when farming assassination missions.
As far as exploiting game mechanics, same is true for relogging to get materials, missions, outside a station, anything relogging gets you other than software bug resets. Walking away from your ship and risking death, yet the game not having the wherewithal to deliver death because player power creep created an unbalanced NPC offering isn't exploiting. It's just daring the game to do something about it.