The cell provider location data is the most insidious. They add noise to it, but the central limit theorem is a real thing and people who buy the data are aware of that.
[1] https://www.nytimes.com/2020/01/15/technology/data-privacy-l...
[2] https://www.vice.com/en_us/article/nepxbz/i-gave-a-bounty-hu...