The scene in AMoL where Demandred lends Taim his sa'angreal, and warns him not to use it against him because he has bound it to himself annoys me rather a lot.

One of the things I like about channeling in the Wheel of Time is that it seems to mostly follow a set of consistent rules, almost like physics. Thus, I feel that a vague concept like using something "against" someone has no place. What does that even mean?

At first, I thought it might cover the case of touching Demandred with a weave while using the sa'angreal, yet what about healing? Touching someone with a weave isn't neccessarily using the weave "against" them.

Then, how about secondary effects, like lightning bolts? Mat was killed by a lightning bolt while wearing his medallion. And what about throwing stuff at him?

And what about other indirect uses, such as using the sa'angreal in a way that hinders Demandred's plans, without actually touching the man himself? Does that constitute using it "against" him?

It seems to me that the concept of binding an angreal to yourself is either pretty much useless, because it doesn't cover everything, or it takes channeling more in the direction of magic by introducing a mystical mechanism to somehow determine wether a particular use can be said to be "against" the owner of the angreal or not. Either way, it annoys me.