if you know what you are doing you dont need to take any kind of a digital asset across a border, everything you need can be obtained at your destination...
border agents are not paid to respect your property, so avoid the opportunity for them to destroy your intellectual achievments via ignorance
However...
==> Your rights at the border. Compared to people and police in the interior of the country, border agents have more power and people crossing the border have less privacy. But the border is not a Constitution-free zone. The powers of border agents are tempered by the First Amendment (freedom of speech, association, press, and religion), the Fourth Amendment (freedom from unreasonable searches and seizures), the Fifth Amendment (freedom from compelled self-incrimination), and the Fourteenth Amendment (freedom from discrimination).
but the agents do have the right to mitigate security/criminal threats.
Having grown up in the UK and known people to have been convicted of crimes, it's never struck me as disgusting or something that is particularly unfair. You're within your rights to refuse to answer a question, but this could be used against you in court.
"Where were you on the night of the killing?"
"..."
Prosecution could well use your initial refusal to answer this question to aid their case in court, even if you then provide some answer within court.
I am very unfamiliar with American law concerning these matters, so I'm not sure how much of a divide there is between America and the UK when it comes to this.
0. https://www.eff.org/wp/digital-privacy-us-border-2017