I heard a couple of cast member stories yesterday with the theme "why do parents take their kids to the Park when they're sick?"
They sometimes have problems with the character costumes getting infested with lice to the point that you can see the fur moving.
While working the Winnie the Pooh ride the cast member noticed one child was obviously suffering from chicken pox. They knew they would have to take the vehicle out of circulation so they asked the parents if they wanted to ride again. No. But the family got back in line and ended up in another vehicle. Again they were asked did they want to ride again. No. And they got back in line and infested yet another vehicle. So three vehicles down all because of this kid who shouldn't have been there in the first place.