The Fourth Amendment does not apply when you are on U.S. Port property; or on a boat, ship, or yacht on the water. If you don’t want to get searched don’t go there. There are signs posted prominently at the entrance to the port property. You can argue all that you want, but those are the rules that have been upheld by the courts. If you are searched and you have over $10,000 cash you are in trouble. If you are on a boat and the Coast Guard boards and finds one gram of marijuana you are in trouble.
Some people stay out of trouble and some people find trouble to get into. That is why I am very careful about who I travel abroad with.
At this point in American history the 4th amendment does not apply if the government official say “drugs” or “terrorism”. Anywhere in the US they can decided you have too much cash and just take it. Too bad so sad.