Yesterday, when I shielded and grounded my Squier Strat, I was thinking about your video because I saw it a few months ago, and wondering whether or not this was really necessary in order to ground the strings. So, I took a multimeter and checked for continuity from the bridge to the tremolo claw. Sure enough, there was continuity; in other words, the springs do conduct current, and do ground the strings. Today, playing the Strat again, it was not necessary to put my fingers on the strings to eliminate the noise: the strings are grounded via the tremolo springs. So, I appreciate that maybe the springs on your guitar are not conductive for some reason, but I would check that with a multimeter to make sure.

I can see that maybe being a better ground-not relying on the springs, but I can also see the wire breaking from the tremelo moving.