In reality it's supposed to be even more strict. They're trying to get around this by having a private company own the cameras. If the government owned the cameras, they would need to get a warrant with a sufficiently narrow target from a judge before initiating electronic surveillance to track the targets' location.
If something is really going on which justifies it, getting a warrant is trivial and probable cause is a low bar.
You say that like it's settled fact. Was the "research" peer-reviewed and published in a reputable journal? Has it been replicated?