If I could present arguments as part of the panel, here's what I'd do to illustrate the points from my brief.
1. Church-Turing is about Emulation. I'd bring my iBook running OS X, and show it emulating 9 to run a CD-ROM I published 6 years ago. Then I'd show it running Virtual PC, to run another Windows CD I published in the same timeframe. It even emulates a VT-100 so it can run Emacs.
Then, I'd show it running MacMAME to run a Video Game from 20 years ago. That MAME is running the code from the original ROMs, and thinks it is on some custom CPU and graphics card is the point about the futility of a trusted client - the computer industry does not oppose the CBDTPA because we're bloody minded, but because it is the CompSci equivalent of legislating Pi to be 3.
Other emulators such as ReBirth or Reason would work too, and are more obviously emulating some other equipment.
2. Editablility. I'd show them how I can edit my kids movies in iMovie or QTPlayer or sequence a CD in iTunes. Then, I'd play the Disney Tarzan DVD that forces you to watch 5 minutes of adverts without being able to fast forward.
3. We are all creators. I'd show them my first-grade son's webpage and I'd show them one of the funny movies that he directed where he presses a button and turns his brother into a banana.
4. They don't trust their customers. If I can get one, I'd put in a Sony 'protected' CD that deliberately crashes the Mac (a felony in some states) to show exactly how much contempt.
5. Set the markets free. Online, my son could compete for customers with MPAA members. Mandating that the computers we use to express ourselves become playback engines for centrally licensed 'content' would set the US back compared to the rest of the world. Along with many others, I came here to work in the computer industry because it is a free country - free in the sense of liberty not gratis. If they abridge the freedom of speech and free markets with these ideas, the US won't be the magnet anymore.
6. The Internet is a huge boon to free speech -over 2 billion webpages are out there, showing people's thoughts, dreams and stories. Whatever you go looking for, you will find. The Web is Caliban's mirror - when I go there I find a community of intelligent discourse, wry jokes, technological assistance and the greatest works of human history, lovingly transcribed by those who care about them.
Oddly, when Jack Valenti looks there, all he finds are thieves, hucksters and crooks.
Another point. The MPAA or RIAA rep will at some point claim that their industries 'lost Billions' to 'piracy'. These are Enron, Worldcom or Anderson Billions. Ask him who audited them for him, and where they show up on the balance sheet.