The "stars" of coaster shows are the rides, not the people on them. Why bother watching a coaster show just to see some celebrity? You can see them all over the place anyway. These are specialty shows for a targeted audience, and they cater to that audience. I'd rather see and LISTEN to someone that is knowledgeable about rides/enthusiast groups than have someone on the screen that's there for looks alone.
Now, if there are celebrities who honestly are coaster buffs, not just doing it for the $$$ or fame or whatever, I'd not have a problem with that, so long as it is honest and not "look at how good I look draped across this lap bar..." Sheesh.
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Po!nt of View: A different look at Roller Coasters.
http://www.crosswinds.net/~justmayntz/thrills/index.html