While that's a lovely fiction created by our government, it really does not pass constitutional muster.
It really is cut and dry as written and not really open to "exceptions".
"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."
It is easy for the government to stay within the law, just issue a warrant stating what you are looking for, but the 4th is specifically designed to stop fishing expeditions. That along with the right to travel freely really makes these laws questionable on the surface.
Kent v Dulles:
The right to travel is a part of the 'liberty' of which the citizen cannot be deprived without due process of law under the Fifth Amendment. If that "liberty" is to be regulated, it must be pursuant to the law-making functions of the Congress. . . . . Freedom of movement across frontiers in either direction, and inside frontiers as well, was a part of our heritage. Travel abroad, like travel within the country, . . . may be as close to the heart of the individual as the choice of what he eats, or wears, or reads. Freedom of movement is basic in our scheme of values.