It’s even citizens leaving and returning internationally (though technically it can be domestically.) Most don’t understand that the 5th amendment doesn’t apply to the customs and border patrol; they can go through your phone and computer.
Non immigrant aliens are not considered people as evidence by their lack of right to bear arms, the other right ascribed to 'the people.'. Courts have held for decades now that they are aliens not people, just not the ones in flying saucers.