Worth remembering: US citizens can play chicken with CBP and lose nothing more than their computer/phone hardware (perhaps having it returned 6 months later). But non-citizens, possibly including LPRs, cannot: if an alien attempts to cross the border with a device they can't unlock "because they don't have the corresponding 2FA token with them" (as one friend suggested they do), they'll be detained, their devices con…
Well they can also be detained, for an indeterminate length of time.
That could put their job at risk ( didn't show up for work for a couple of days with no explanation ), their mortgage, their house...