You don't even need a source for that its common sense, if you want a source try to find the CIA/NSA/GCHQ employee handbook or whatever material they give to ne

You don't even need a source for that its common sense, if you want a source try to find the CIA/NSA/GCHQ employee handbook or whatever material they give to new users. Its the same idea that malware operators test out mobile malware in faraday cages so that the malware can't jump devices.