Either too much St Louis action...or possibly they have an opinion on the game themselves. Olympic, for one, is well-known for straying from the norm and trying to get people on what they feel is the wrong side (and they're pretty good at doing that!).
My guess in this case is it's just too much StL money though. All the more variety. In the long run that can only help the players. Also why you should have more than one book.