First, people were willingly installing COVID-19 contact apps to alert them if they were in contact with a confirmed-positive case. Despite all of “us” (security-paranoid people) shouting at the top of our lungs that This Is A Bad Idea.
Second, your phone is constantly listening to a list of SSIDs and bluetooth identifiers to connect to and broadcasts a small amount of info - like your MAC address -, which can uniquely fingerprint your device. Supermarkets, for example, have used this for years to track shoppers. They can easily track your phone without GPS just by listening what it broadcasts and where from. And it is also then not a surprise when Apple decided to remove the functionality to turn off WiFi and Bluetooth from the “drawer” and instead of for it to only “disconnect from nearby networks until tomorrow.”
Here is the article about WiFi and retail stores https://lifehacker.com/how-retail-stores-track-you-using-you...