Re: Files are not testimony
Files may not be testimony, but a police agent seeking access to a phone may not have warranted reasons to search the phone, either. Our US Customs and Border Patrol will take away phones and laptops at airports without articulating why. If an explanation of what is sought cannot be made persuasively to a magistrate judge, sufficient to authorize a warrant, then certainly a traveler should not be compelled to unlock a device. That is why the fingerprint-unlock or facial recognition-unlock is so fraught with peril - search can be made by a cop who wants to look and see if anything is arguably criminal, without knowing in advance what could likely be there. Let a cop walk in your unlocked front door, and see what he finds walking through your house, without needing a warrant...