I'm wondering if some types of crystal can absorb or distort the signals enough to make you harder to identify. I mean I guess you'd be "that guy with the crystals in his pocket" and would be easy to correlate to CCTV flock, but if everyone does it it could create a layer of obscuration.

Especially things with piezoelectric and/or electromagnetic effects. I'm thinking mainly along the lines of quartz, tourmaline, pyrite, tiger's eye (hematite/jasper), shungite, etc.

It would be worth experimenting with if anyone tries that open source software another commenter linked...