My very simple thoughts on this matter:
The rivet is a conductor. We have no way knowing if the coating between the rivet & the blade is compromised or gets compromised during use. Because of that, if due to field expediency, you needed to use a scrap yard on a live wire find another way to insulate yourself & don't trust the knife. Be it making a bit of a poleaxe & lashing the handling to an insulator or something else.
Anything else and it will be a crap shoot which could lead to serious injuries. <img src="/ubbthreads/images/graemlins/frown.gif" alt="" />
OR DEATH!!!!!
I bet Res-C is fine, it is just that lanyard bushing that others already mentioned.
I only know of one knife that advertised compleat insulition from the blade and that was the Gerber LMF they had a picture of one that a US sniper had used to cut big eletrical cords that were going to a search light aimed on finding him and his spotter, the blade had a big melted chunk out of the center but he was alive to tell the story.