text:  Is that a risk I'm willing to take? I mean, John Cawley seems like a good guy, but I don't know. After what I learned today about the science of celebrity endorsement, I think it's a pass. But I do appreciate the offer, John. I would also like to thank John for the good conversation we had today, along with Zab Johnson and Al Roth. I am curious to hear your views about celebrity endorsement. Send us an email. We're at radio at Freakonomics.com.