Absence of normal phone activity which correlates with prohibited activities can also arouse suspicion. If I wanted to prevent the spooks from thinking I was a

Absence of normal phone activity which correlates with prohibited activities can also arouse suspicion. If I wanted to prevent the spooks from thinking I was away from my phone, I'd probably use some sort of robot to move the phone around and randomly unlock it using a fake fingerprint. If you do that, your phone actually turns into an alibi, placing you somewhere other than where you actually are.