"If an enemy's speed is reduced to 0 (Through Drain Speed or Damage Speed) not only is it rendered immobile, but it will cease targeting the player and won't try and defend itself if attacked, even if it has ranged attacks or spells. In this state it can be repeatedly sneak attacked from behind."
Has anyone tried this? How well does this work? Obviously the combat benefits of this effect would be great, but what I think would be cool is if it could be used against friendly npc's to psuedo-blind them to get away with crimes that they can't see anymore. If I drain a shopkeeper's speed to 0, can I steal in front of him without him noticing? If I use the spell on a guard, can I get away with trespassing and stealing without him adding a bounty? What's the limitations of this?