In a Vanity Fair interview with Kevin Pang, Teller explains that when he and Penn do a trick like the cups-and-balls-with-clear-cups, they’re not doing it to piss off other magicians:

We were taken to task by one magician who came to our show and took a swing at Penn in the lobby for the evil that we were doing. Penn said, “Why don’t we just go to the diner and have a chat?” So this magician sat down with us and said, “All right, whose side are you on anyway?” That’s the fundamental problem with much of magical performance. Merely because a magician is trying to create a moment in which a spectator is astounded, the magicians often conceive of themselves as being in opposition to their audience. That is something Penn and I are violently against. We do not believe the audience is stupid. We believe many, many, many, many — perhaps most of the audience — is a great deal smarter than we are. Therefore, they need to be shown the respect to be treated as peers.

Later, the subject turns to the hit CW show, “Fool Us,” which is the best showcase magic has gotten on television in a very long time. Each week, Penn and Teller try to figure out how the magicians have done a trick, and then explain their understanding in a way that doesn’t actually reveal anything to the home audience, but lets the magicians know they know what just happened:

When Penn talks about magic, he tries not to spoil the trick for the home audience—that takes away the fun for people who want to watch it over and over again, or people just delighted by the effect. So Penn deliberately uses jargon terms that will communicate to the magician and to the community of magicians that we do know indeed what’s going on, without wrecking the trick for the home audience.

There also really is, precisely, a way to encourage people who are interested in magic to learn more. If we say, “Does the term ‘breather crimp’ mean anything to you?” That takes somebody who might be really interested in card magic to Google “breather crimp,” and they’re going to learn a really cool thing that they might be able to use. 

Read the full interview with Teller — including some insight from Pang on watching “Fool Us” that I agree with completely.