There is a long standing a 4th amendment exception for customs inspections when entering and leaving the country. All of your belongings are subject to inspection in a search for items which may be charged a duty, or are contraband.
I know you might not agree with that, but it is good to know information the next time you get to customs.
There are 4th amendment exceptions for just about everything, these days. I understand that. And I don't agree with it. I doubt the founders would, either.
And I don't have to worry about customs, because I don't intend to leave Texas, ever again.
/johnny