Now imagine a significant portion of your students are missing the prerequisites. Do you really think these professors are up in arms about a few students who

Now imagine a significant portion of your students are missing the prerequisites. Do you really think these professors are up in arms about a few students who don't have the prereqs? It obviously must be a large enough proportion to worry about. It's no longer "if a student somehow makes it into my class", it's "many students are currently making it into my class"