TheBOSman

CBP can't deny you entry to the USA as an American citizen by law, but in theory they could detain you about as long as they want. And there's almost any number of things they can (and will) pull if they don't want you here (see here: https://papersplease.org/wp/2014/01/...urn-to-the-us/) that can significantly delay your entry. And, they could simply seize all of your electronic devices and not return them to you for weeks/months (which might be the best actual pragmatic reason to have a burner phone when travelling). And this all presumes they accept that your USA passport is legitimate and not a fake, which opens up a whole different can of worms. And, of course, this only really applies to when one is entering a country where one is a citizen; had I not unlocked my phone for the agent at CBSA (Canada Border Services Agency) during secondary inspection, I presume they would have simply denied me entry, which would have likely caused significant issues on any later attempts to enter Canada in my lifetime, as well as have been something I would have had to list elsewhere if entering other countries (some countries ask if you've ever been denied entry to any country), potentially causing issues there.

It's one thing for people to talk tough, but for many (not all) a full-out tinfoil hat approach is less than desirable.