Not only is it likely very easy/possible to track everyone with a phone but it has now got to the point where "movement without a cellphone present" is a red flag.

"Hey...why is this guy suddenly deviating from his normal routine? License plate readers show him 100 miles out of his normal area. Why did he leave his phone at home?"

Just like social media. Not participating is considered suspicious.

Anyone with Govt. level access (or billionaire level access) can very easily put all this data together.