My line would be drawn at the "general use" test, although it would have almost the same practical result as the judging test. If an activity is almost soley used for the purpose of competition then, yes it is a sport. This is what would eliminate me from claiming walking to my mailbox is a sport, even if I formed a governing body with a couple of my neighbors, we judged each other, and handed out trophies. This is not intended to be a competition. Neither is dancing. Dancing's general use is an exhibition. Neither is cheerleading for a school. cheerleading's general purpose is to lead cheers/build spirit. Freestyle snowboarding, skateboarding - not sports. Golf and even mini golf, yes, both were created with competition as a backbone element. Horse jumping, yes, I'm pretty sure the only reason that's done is to compete. Curling is a sport, no other purpose than competion.
Bottom line, I would not put something in the category of a sport just because people in an established activity have gotten together and said, "this is fun, let's get some judges and compete to see who they think is best,"
The only other factor I would consider is a physical element that cannot be performed on a whim by the general populace. Poker is out, as most everybody can pick up cards. Chess is out, Bowling is in, golf is in. Theoretically, video games could be considered depending on the genre.