Yes, in fact government agencies like the Secret Service [1], CBP [2], IRS [3], and others frequently purchase it to circumvent warrant requirements.

[1]: https://arstechnica.com/tech-policy/2020/08/secret-service-o...

[2]: https://www.wyden.senate.gov/news/press-releases/wyden-warre...

[3]: https://www.vice.com/en/article/m7agpa/irs-location-data-ven...

The information being sold there wasn't from mobile providers, they were collected by apps. See the first paragraph of the third article: "location data quietly harvested from ordinary smartphone apps over 10,000 times". The same applies to the other two articles.

Yes, at least in the recent past.

https://www.vice.com/en/article/nepxbz/i-gave-a-bounty-hunte...

They promised to stop, but I’m not sure I believe them.

Putting on my tinfoil hat, I'll note that mobile providers depends on Brown University for antenna space on at least three tall campus buildings.

A few years ago you could look up any cellphone number’s location on a public website:

https://krebsonsecurity.com/2018/05/tracking-firm-locationsm...

Why would they be sued? It's all right there in the contract in black and white.

And, naturally, all the customers carefully read through the contract. /s

I don't even know what could be done to stop this stuff at this point? I think it's too far gone.