I read up on this [0]. It looks like it helps to have a newer phone, and even then this feature is inconsistent across models, with some phones spewing non-random frames even when wifi is off and/or depending on how location services is configured. Although I would assume the feature will continue to be better implemented as time goes on, it doesn't look like something that is protecting most people yet.
I read a bit about bluetooth tracking [1]. Apple and Google both apparently support this kind of tracking via apps, and a lot of apps use toolkits made by advertisers that do this. Apple has been selling their iBeacon devices that can be located in stores to track people. Here's [2] something about google tracking via bluetooth even when bluetooth is turned off.
I heard it's a lot more than the specific store app tracking people in that store. I've heard that there are tons of toolkits and sdks used to build apps that have this kind of tracking built into them, for example [0]: 79 out of 123 manually tested educational apps tested were sending data to 140 advertising companies. Another article [1] saying that Apple has done nothing to stop this, either.
I'd assume that anyone with location services enabled and/or more than a few very well chosen apps is being tracked via these methods. I assume that most popular apps include this stuff, and most people are being tracked. The more I look into it the more pervasive it seems to be.
I read a bit about bluetooth tracking [1]. Apple and Google both apparently support this kind of tracking via apps, and a lot of apps use toolkits made by advertisers that do this. Apple has been selling their iBeacon devices that can be located in stores to track people. Here's [2] something about google tracking via bluetooth even when bluetooth is turned off.
[0] https://www.theregister.com/2021/05/18/wifi_tracking_failure...
[1] https://www.nytimes.com/interactive/2019/06/14/opinion/bluet...
[2] https://qz.com/1169760/phone-data/