Subject matter expert

I understand that sometimes speakers are selected because they need to learn something, and other times they are chosen because they are expert on the subject. And sometimes there are people who are asked not to speak at all!

As I was drawing this, I kept thinking that Arie Van de Graaff (aka, the Mormon Cartoonist) had drawn something similar. This gag isn't a blatant ripoff; rather, it's a variation on a theme.