[TeMPOraL]

It's sickening to think that you're going to have to engage in actual electronic warfare with the world around you just to buy some milk for breakfast.

[hannasanarion]

In order to save yourself from, what exactly? The local grocer having a picture of you in their store?

[TeMPOraL]

What do they need that for?

Also, such systems are primarily used by chain shops, and provided by specialized companies. Both mean the data gets shared to multiple entities.