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.
