Tom Scott's just done a video about this: <a href="https://www.youtube.com/watch?v=MVI87HzfskQ" rel="nofollow">https://www.youtube.com/watch?v=MVI87HzfskQ</a>
sounds like a great application for DNS spoofing pool.ntp.org to a local server that always responds with 1 Jan 1970<p>unless ios devices get their time from cell networks or whatever