One time, several people cheated on physics homework (apparently in a very obvious way), and the professor took fifteen minutes out of the next lecture to basically say "you know who you are, you got a zero, and if I see it again, I'm going straight to the Provost."
Princeton is very much optional and is a school for future elites. They're supposed to produce CEOs, politicians, and Nobel prize winners. So the standards should be different.
Of course, expectations are a part of the problem. Many kids go to Princeton or Stanford or MIT because they had wealthy parents who really wanted their kids to go there. And many of these kids are mostly interested in computer games, weed, and the opposite sex. A combination of unmotivated students and high academic standards lead to predictable outcomes.
They also produce more "elites" than "elite" schools do if you go by executives at F500 companies and politicians.
Are we going to pretend that Berkley, Michigan, UNC-CH, UVA etc. do not produce world class educations from world class people?