What if they purchase the information from a company peddling it rather than compelling cell phone companies to hand it over?
For an example of what can be done with such purchased data, one project at a previous employer was: - identifying all cell phone #s which would regularly appear w/in a certain radius of any State Police Barracks - disambiguating that from people who lived/worked nearby and/or who met certain criteria - determining the income and certain other criteria of the remaining numbers - identifying the home address of the re…
The only solution in that case is to make it illegal to sell the data. And that's never gonna happen in the US.