Avi Wigderson taught a mini-course on expanders in Paris last week. I spent some time there learning about expanders, and some time learning about teaching.
When I present an algorithm or proof in a talk, in order to convey the main ideas, I sometimes ignore side concerns, which sometimes makes me take liberties with correctness stricto sensu. Avi takes that approach and carries it to an extreme: when briefly presenting a research direction, he may choose to briefly outline the prettiest algorithm, while briefly citing only the most important paper on the subject, even if there is a mismatch between the result outlined and the paper cited! I would not dare do that (at least not on purpose), for fear of catching hell from authors. But it is morally doing the right thing: giving a pointer to the one paper interested students ought to look at, while attracting them with hints of the most elegant results.
It's sacrificing accuracy in the details, so as to better get the essential ideas across. In fact, it's also sacrificing some accuracy to beauty. It's an anti-Pharisee stance: Pharisees, I am told, were so obsessed with rules and with following every detail of every ritual in exactly the right way, that those regulations obscured the overall purpose of their religious practice.