How to take a large chunk out of your leg - step 1

A teenage kid came into the store yesterday looking for some braided steel cable. Showing him our selection I asked what he needed it for.
"Oh, I'm going to replace the plastic line on my weedeater with it."
This sounded like a seriously bad idea to me and I didn't hesitate to tell him so. It turns out his plan was to remove the plastic line and wind up a few feet of 1/16th inch braided steel cable onto the spool. I pointed out that the plastic wedge that's installed on the guard to cut the plastic line would be shredded in no time by a steel cable. In fact, so would the guard, and very shortly thereafter his leg.

In doing a bit of research I came across this forum thread where some random guys on the internet opine on the same subject. It looks like there may be some kind of titanium wire that would work like the kid was thinking, but that the braided steel cable will just shred after a few rotations.