I’m paywalled so can’t be sure, but do they explain how theses apps were able to track others app usage in the first place without breaching their sandboxing pledge?
The article doesn't go into detail, but my guess is through the use of MDM profiles, or possibly local VPN filtering.
This would be even worse regarding privacy!!!
Likely Accessibility API (or/and undocumented APIs).
The Accessibility API on iOS cannot block opening apps to my knowledge, and using undocumented APIs are a pretty good way to get removed from the App Store immediately as opposed to with a warning to change your app to "comply".
In at least one case: Then, with Mobicip’s deadline just a few days away, Apple responded three times to his earlier detailed questions — with virtually the same message: “Your app uses public A.P.I.s in an unapproved manner, which does not comply with guideline 2.5.1 of the App Store Review Guidelines.”
I looked through Mobicip's support materials and they install a remote management profile.
And is that respectful of the AppStore rules? I’m not sure people realize that App that provide system wide functionality using borderline workaround are only one step away from becoming straight spyware.