The devil is in details, in other words, it matters how the sandbox/isolation is implemented.
I would expect this: some malicious code requests a service object from the OS. An implementation is returned, but if no permission is granted by the user, the said implementation does nothing. There should be no data in the service object that can be used to glean any information about the internal state.
The only thing that can be detected in this design is that the service object does nothing (and even then, perhaps, it is possible to emulate the service behavior such that the code thinks everything is fine).
