That seems unlikely. I think there already was a tethering app which Apple pulled from the Store but didn’t pull from devices. I do think that Apple is serious when they say that their ability to remotely pull apps is reserved for malware.
The much more elegant solution for Apple is to make this app silently stop working with the next OS update.
That’s very interesting. Wouldn’t it be very easy for Apple to break the app with an OS update? You would almost expect that an app stops working after so many OS updates (not because someone purposefully made it stop working but rather coincidentally).
Chances are NetShare reused existing code from an open source SOCKS proxy implementation, which would probably just use standard UNIX APIs. Combine that with the simplicity of the GUI, and it's very possible that none of the APIs it is using have changed since release.
The much more elegant solution for Apple is to make this app silently stop working with the next OS update.