A friend who’s a lawyer told me they are allowed to search on way out. But if an encrypted device they might not get much useful.
The grey area is what if you don’t help? Can they seize the device? Deny your flight? What if they just strongly imply the airline shouldn’t let you but it’s technically the airline denying? What if you go to Buffalo and walk?
The edge cases are more around how much aid you must give to the search and if they can take the device.
Personally, I encrypt my phone and plan that if it’s seized, taken out of my sight etc I’ll trash it. I find that a couple years old phone works just as well for maps and signal.
