The strongest advice and one I've heard from several experts is don't travel out of the country with your phone. Joe could get a pay per use, or have a 2nd phon

The strongest advice and one I've heard from several experts is don't travel out of the country with your phone. Joe could get a pay per use, or have a 2nd phone to use just for travel. Changing just the vault password would be useless. I'm unaware of what level of tools border control has at it's immediate disposal, but they do make a copy of your phone contents from what I've heard, and passwords can be decoded from that after the fact. Once you get it back they've already got what they want. 2nd best to that IMO is set phone to wipe after a number of incorrect password attempts, which is good security in case a phone is stolen anyway. It might not be considered "compliance" however, but you'd be handing over your phone (given ability if stopped to enter wrong password in x number of times before asked for phone). But after the fact, being caught in the situation and complying, I would suggest completely wiping the device, deleting/recreating any account that isn't essential, changing passwords for all that are and enabling 2FA as possible. And non-tech related, carrying the # for ACLU or a attorney written down is essential for anyone who might be flagged.