Since I work for an educational institution, there is potentially FERPA protected data on my drive. In some instance we also deal with HIPPA data. It's also interesting because my password manager stores it's data as encrypted files on that drive (mirrored from the cloud). I'm certainly not unlocking that either.
Another way of looking at it: You can write whatever you want on paper and sign it, but that doesn't make it enforceable. You could sign a document that makes you a slave or puts up your children as collateral for your ISP bill, but those agreements would be scrap paper (or evidence for the prosecutor).
(a) They are regarded as seeking admission and they are found inadmissible. Refusing to unlock their device will not make an LPR regarded as seeking admission as it’s not a reason listed in INA 101 (a)(13)(C): https://www.uscis.gov/ilink/docView/SLB/HTML/SLB/0-0-0-1/0-0...
(b) They are deportable. Simply refusing to unlock a device in itself will not make someone deportable as it’s not listed in INA 237 “General Classes of Deportable Aliens”: https://www.uscis.gov/ilink/docView/SLB/HTML/SLB/0-0-0-1/0-0...
Saying that, the only people who cannot be denied entry to the US are indeed USC.
Probably until some court rules that a client making the information seem local to facilitate access is legally equivalent to having that information local (and hence not under protection of 5.1.2).
Most likely followed later by some other ruling that a browser can be considered such a client.
> If an officer is unable to complete an inspection of an electronic device because it is protected by a passcode or encryption, the Officer may, in accordance with section 5.4 below, detain the device pending a determination as to its admissibility, exclusion, or other disposition.
Section 5.4 elaborates further.
Also, I found 5.1.2 interesting:
> Officers may not intentionally use the device to access information that is solely stored remotely. To avoid retrieving or accessing information stored remotely and not otherwise present on the device, Officers will either request that the traveler disable connectivity to any network (e.g. by placing the device in airplane mode), or, where warranted by national security, law enforcement, officer safety, or other operational considerations, Officers will themselves disable network connectivity.