That said, I have to wonder whether the interviews are really necessary in most cases. For institutions that it is familiar with, I suspect Amazon could do just as well hiring interns purely based on their grades in relevant courses. If you reliably take 100 interns from Berkeley or Waterloo, say, it shouldn't be hard to figure out which courses count.

At worst, doing things this way would be much easier. Who knows, maybe it would work even better, by eliminating unconscious bias or something.

By all means keep the interview path for special cases with odd backgrounds.