Border Search
Those who hold no value for their privacy rights are doomed to eventually lose them. We see from some responses in this thread that the expectation of privacy in the face of government intrusion has slowly eroded. You have to decide whether you want to be the government's gerbil or your own fucking man. That is really the choice that is being made here.
For Eager Beaver: Your initial post speaks of the necessity for a warrant. GENERALLY SPEAKING, there are no Fourth Amendment protections at the border. No warrant is needed for a search, nor is reasonable cause. Border agents have a virtually unrestricted right to search, which is based on the sovereign's right to protect the nation against threats entering from abroad. You may find the law on this very easily by Googling "Federal Constitutional Law, Fourth Amendment, Border Search". Now, I have not yet read the Supreme Court's opinion of several days ago, but I doubt I will find anything contradicting this basic principle, which I learned in law school about fifty years ago. I should have the opinion today or tomorrow and will study it carefully. If I see anything that changes this body of law I will, naturally, give you, and anyone else who is interested, a postscript.
Given that at the border the agents have a royal flush and I have, maybe, a pair of threes, I employ the charm offensive: I use the word "Sir" ad nauseam; I smile a lot; I do exactly what they tell me to do and try to seem cheerful about it; I've shaved; I am wearing clean, neat clothes; I keep my USMC sticker on the left side window. I'm LEXUS anointed. I've had one random search and, last time through, an hour or so getting two kittens I agreed to save from the chloroform into the good old USA. No real problems, agents polite and professional.
Good luck to everyone and remember, the border is no place to play games with cops.