Excellent thoughts, ya'll. One more thing I can add to the conversation.

In TDR, the first time Moiraine used balefire, she took out a bunch of darkhounds. She was hopeful that Sammael wouldn't notice it, given their distance from his city. That suggests (directly, mind you) that balefire can be sensed by a channeler of the opposite power in the exact same way that they would detect a large channeling effort from someone who uses the same power!

So is balefire an exception to the male/female divide, channeling-wise (no seeing weaves/knowing what the other's doing)? Was it false worry over the talents of a supposedly god-like Forsaken? Or could it be something else?