Not as in Harvard Vs Yale style guides - I mean in the context of applications.
If you want to get into a prestigious course, you need to hit up two or three people who will say you are good. Easy enough for people who run in the right circles. Embarrassing, awkward, maybe even a dead end for those who don't. Many references are meaningless because they're about one of 300 undergraduates. Few academics will refuse a reference if asked because they know the system is kind of a racket.
We should get rid of the requirement for references and replace them with backgrounds checks and in person interviews.
Or we would if universities were actually serious about expansion access. Which they're not, really.