Hat/CSP with IR LEDs under the brim with a small latching switch in the side band, allows me to easily turn on when approaching the self checkouts, floods the sensor not allowing a good image to be collected.
I have been followed through a shopping centre when using this, but its not anything they can legally stop me from doing currently.
Next step I'd to pulse the led array randomly at 100-300hz which will increase battery life and hopefully produce a random stripe / saturation pattern to the video/image.
 Not fool proof but simple privacy hack against image capture.