How Novel Are Random Searches?

Maybe I'm hopelessly ill informed, but haven't people crossing national borders been subject to random searches by people in authority since... well since we've had such a thing as borders? I've seen in various places people saying things to the effect that this is something new and very, very bad caused by paranoia over terrorism. But it seems to me that I've read about boats pulling fast for the shore to avoid revenue cutters in stories from the early 1800s. This seems to imply that conveyances have been searched for contraband by national governments for at least two centuries if not, much, much, much longer.

While it might be argued that a controlled border between the US and Canada is about as sensible as one between modern France and Germany that is a separate and different argument. And I'll note that the process of getting that open border between the different nations of Europe was rather lengthy and involved.

I am in favor of a more open border with Canada, but regardless of jokes about it being the 51st state Canada is a separate nation with its own laws, politics, etc. It seems a little silly to me to assume that going to another country is normally like going across town to visit a quaint ethnic enclave.