Just tinkering with a pair of those - the glove itself doesn't activate the XPS 15's touchpad unless my hand is in it. There doesn't appear to be any conduction between my hand and the contact point on the outside of the glove according to the resistance measurement function on a good handheld multimeter, so it's not clear to me how the gloves work. But, I have managed to get a piece of copper foil, kapton, and some wire to activate it. I guess the touchpad uses some kind of RF, which makes sense...

Will try to make a test jig that consistently triggers one of the irritating behaviours, but my touchpad R&D period (aka conference call) is wrapping up, so it'll be a while.

Usually capacitive touchscreens sense a capacitance difference, which is set by the dielectric permittivity (ε) of the material above. Ours is close to water's, but an insulating layer from another material will yield different measurements.

I am guessing that touchpads use similar tech.

A fun fact is that capacitive sensors such as the one used on touchscreens are fully 3D-capable, but that seems to be rarely used (I've seen it once or twice on Samsung phones, and Sony's "glove mode").