> I believe shopping malls often use such signals (wifi, bluetooth) to track what your travel pattern through the mall is. They know what section of the store you spend most of your time in and what storefronts you stall at.

Yes, I remember Cisco had a product like this all the way back in 2011. They could pinpoint a customer to an exact position inside a store using triangulation, they would know which shelf you spent time in front of etc. In the 15 years since then, I expect the technology is much scarier and intrusive.

iBeacon. They know what shelf you're standing in front of. What products you touch and read.

Ever been in an Apple store? Look up. In the dark voids between the edge-to-edge backlit ceiling. There are secrets there. Watching you.