This is the end product of the grub-grip.
 
Gut some 24 gage coated floral arrangement wire

Snip a section off and line it up to the line tie post:

Wrap one end around the post once and tightly:

Snip off one side close and use pliers to make it tight:

Bend the wire as shown:

Swing the wire into the lure and it will never slide back.
I buy jigs with no lead collars which damage soft plastics and shortens their usefulness.
I use the same wire to keep skirted bass-jig tailers from falling off.

Hey, that's clever. I like it. I use similar ball head jigs quite a bit and will give this a try.

Tip: instead of wire cutters, nail clippers do a good job of cutting the one side close to the line tie post. Also, if you use light jigs such as 1/32 or 1/64, a smaller diameter wire does fine.
 
I use the same idea on my bass jigs to hold trailers in position. Below are copies of trailers I use poured from plaster molds. The trailer grip is made by wrapping the wire around the curve of the hook after the trailer is in place but not too tight for better trailer action. 
(I attach silicone skirts like the one shown below using a wire zip tie, not thread.)
 

plaster molds: