CBP is often deliberately vague about this sort of stuff because they don't want people to know they have a right to refuse to answer questions, refuse to enter phone passwords, refuse to show ID away from the border, etc
CBP's entire process of "inspecting" US citizens returning to the country only "works" because 99.5% of US citizens answer their questions, and many of those citizens answer because they think they are required to, or they are afraid of what will happen if they don't.
If people knew they didn't have to comply, more people would refuse, and CBP wouldn't have the manpower to detain/hassle/intimidate all of them, and they would have to just stop asking Americans intrusive questions.
Originally Posted by
battensea
But if you refuse to answer or allow them to search your belongings, what is to keep them from holding you in the back room for several hours?
CBP officers can search your belongings without your consent. You have no right to refuse that. You don't have to answer questions. I always offer to answer any questions regarding my citizenship, where I was born, etc.
They can absolutely delay you for a few hours, because as of now, almost everyone answers, so they have time to retaliate against the few who don't. I usually get delayed 1-2 hours myself.