I'm not sure I read the parent same way you did. What he proposed is a way to circumvent border data check by having no data on your devices during that time. If there's no encrypted data then device passwords will do nothing for them.
So throw the phone in a gift box and tell them you're bringing it to a friend who lost theirs because of the exchange rate. Plausible deniability, right? Throw your SIM card into an old Nokia 3310 if you're worried about them thinking you don't have a working phone...
