The constitution doesn't disappear at the airport. The man is a US citizen. He could have remained silent, and they would eventually have let him in.

Relevant reading for you: https://www.aclu.org/documents/constitution-100-mile-border-...

And no, they wouldn’t have denied him entry, but they would have seized his device.

I enjoy the funny implication it creates, that then perhaps if you're entering US in 2026 it means there's something wrong with you.