No they don't. Besides the obvious flaw of having to download and open an app to check if you're being tracked, they just don't work. They all have sub 2.5 rati

No they don't. Besides the obvious flaw of having to download and open an app to check if you're being tracked, they just don't work. They all have sub 2.5 ratings on the app store. The only ones on that list that don't have terrible ratings are general bluetooth scanners and they don't tell you that you're being tracked, just that there's one nearby. Compare that to iPhones where you'll get a notification if one is following your movement, they're functionally useless if you don't think you're being tracked.