John is worried about traveling overseas and then having his mobile device or computer taken away and being forced to unlock it. Leo says it doesn't really happen all that often, though they do have the right to do it, and it hasn't been ruled on being unconstitutional just yet. He'll have to worry when they take his device into another room. Chances are, they've cloned the data or even installed something to monitor him. At that point, if he's security conscious, the only thing he can really do is replace the device to be sure he's secure.
Recently, privacy advocates have become aware that US Customs and the TSA are demanding travelers turn over passwords to their social media and demanding travelers open up their laptops and mobile devices to gain your data. Leo says that is clearly a violation of privacy and the fifth amendment. That passwords and fingerprint ID should be protected. Leo recommends turning off all your devices while you're re-entering the country. But they may detain you until you do. So be ready to call a lawyer.