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="" />
Yes, looking at the pics on the SY website, the rivet does have definite contact with the handle (how else is it suppose to stay in place without some sort of adhesive?). If you keep your hands away, as Kraz said, from the steel rivet it should fine. That is, if Res-C has good electroshock insulating properties. That's what I kinda want to know.
You are right about using something else as an insulator, but you don't get as much control. There is still a need to push down on the knife.... I guess you could make a naginata and just slam the edge into the live wire and it would just severe it. Though what if you have nothing? <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />
Honestly, though, if anyone here on the forum is gonna do live wire cutting, I'm pretty sure they'd be carrying a electroshock tested wire cutter.