>Security cameras around a bank only track stuff within a field of view from the bank. A cell geofence could be millions of people if it's drawn in midtown.

Given the ubiquity of security cameras they can just canvas local businesses and ask them to give it up. Given that warrants are involved, they can't even refuse.

A business can refuse a warrant, but it takes a legal response in court. Their attorneys need to convince a judge the warrant isn’t necessary - that it causes a bigger burden on them than the benefit to the public. Most businesses will just comply because it’s not in their interests to spend time and money on it.

Sometimes a business will challenge a court order if it’s about their own customers, employees, owners, or business dealings. The information requested should be relevant to the investigation, minimal to be helpful, and create as little burden on the business as is practical.

Also, if you’re not the subject of the investigation it’s often a subpoena rather than a warrant. There are major differences between these types of order in the US. A subpoena is an order to produce the evidence. A warrant is an order that allows law enforcement to seize it, using force if needed. As someone who has dealt with law enforcement requests for business data about customers quite a bit in the past, it’s often a simple request first and a subpoena otherwise.

Yes! That would be fantastic! They would need to approach many people, each having the ability to question the motivation! Or, they would need to convince a judge and obtain a warrant.

This is the disaggregation of power of surveillance.