Right. There is definitely the opposing school of thought. The argument against it is that the word "Warrant" was a generally-understood term at the time which applied to a specific British practice and that the term doesn't precisely mean what we now call a "search warrant". And, of course, administrative searches aren't the only ones that don't require a search warrant. Other exceptions are things in plain sight (perhaps one could argue that it's not a "search"), situations where there's no expectation of privacy (e.g., one's front porch or discarded trash), a search incident to an arrest, a Terry stop, "exigent circumstances" (e.g., somebody calling for help), and so on.