The OS can stop an app from using certain APIs. This has nothing to do with the walled garden. ios tells you when an app is using your location in the backgroun

The OS can stop an app from using certain APIs. This has nothing to do with the walled garden. ios tells you when an app is using your location in the background, it can do this for side loaded apps as well. It then allows you to disable it for that app, which it an also do for side loaded apps.