>It’s legal for Perry to search people without probable cause, a warrant, or a dog because travelers supposedly realize that they have the right to decline to submit to his searches.

We need to extend the Miranda Warning to circumstances such as these. "You are not under arrest and you have the right to refuse a search. If you consent to a search, and something illegal is found, it can be admitted into evidence against you in court." If every interaction started with those words, you'd see a lot more people exercising their right to refuse.