Seems like there might be at least a cottage industry in small wearable devices that would foil this kind of thing.

Though, extending this thought experiment a bit, if you asked the average shopper how much they would pay for such a device, I’d imagine the most common answer would be nothing, since the average shopper cannot perceive the cost to them of this surveillance.

Which in turn suggests that maybe a better countermeasure would be some way to show consumers what those costs to them are, in estimated dollars.