I think a lot of radio hosts do that, not just Bob and Tom. I mean, if they don't laugh, it's just kinda dead air. And most suck up to the host anyway. :p
Nice pics of the prop and the close-up! I is funny how the SE costume looks so radically different than the earlier shots. What is wrong with them and not noticing such things? Sure, pobody's nerfect (in Australia), but it's not even subtle.