I know malls track peoples movements throught them and thats creepy as fuck too, though I dont think they tie IDs to individuals, just monitors where people move throughout them.
The rest of your post makes no sense, yes obviously peole can tell the diference between commuters wanting coffee and people on a night out getting drunk. But that is very different to having a label on everyone saying “came from my mistresses house” or “came from my weed dealer” on each person, which is more akin to the level of detail given by referal links.
“Knowing where people come from” does not imply ID’ing individual people, which is why I specifically mentioned that Mozilla technology. The legitimate interest is in aggregate data, and yes “lots of people come here from the brothel” is legitimate data. “This particular person did” is not: If you wear a suit and happen to come with the office crowd doesn’t mean you’re an office worker, you could be a travelling salesman.
