It depends entirely how they're afking. If they're sitting at their comp doing something else and just moving now and then that's perfectly legit. Sure, it makes them ******es, but that doesn't exactly set them apart from the majority of the player base.
If they're using a third party program to automate it, then that's reportable.
The solution to this issue is simple. No base rewards. Give commendations for ONLY objective related actions and have the total points earned multiplied if you win. Rewards would then be based on contribution leaving afkers with nothing and giving people an incentive to try and win, rather than just deathmatching like newbs.
The downside is that it would require bioware to actually think about what would give commendations. ie, damage/heals near a turret, not elsewhere, treating the ball carrier the same as a turret in aldaraan point wise, etc.