
The FBI, through its Director, Christopher Wray, testified before Congress that the FBI does in fact buy private location data from tech companies and data brokers. Though Christopher Wray stated that the FBI does not purchase location data anymore, the FBI has lied in the past regarding its surveillance tactics, so it can be assumed that they are still engaging in this behavior.
Even through Christopher Wray’s own words regarding this practice, he now claims the FBI goes through “court-aided processes” to get this data. Keep in mind that in terms of surveillance, the US Government generally uses what are known as FISA courts. Courts to which the FBI has itself been caught supplying false information to get permission for surveillance through these courts, for example. Even then, it’s well known among both the US Justice Department and the US Intelligence Community that FISA is a rubber-stamp court; they generally do whatever is requested of them.
Either way, it’s time to look into phones such as burner phones or items of interest such as the Pine Phone, for example.
While yes, the US Government tends to be damn good at their job at surveillance, it is best to make it as difficult as possible to do so.