Reversible Baseball Cap 2

There are 30 major-league baseball teams, 15 in the National League and 15 in the American League. Already widely available are baseball caps featuring the logo of one team. In theory a cap could be turned inside-out and put on the head; imagine that such a cap now displays a different team logo. With appropriate stitching (3 layers, with a black cloth layer in-between to prevent any visibility of the "inside" logo) it should be very difficult to tell that this is a 2-logo cap.

The company making these officially licensed caps (you license the use of the logo, so you don't necessarily have to tell the baseball owners about these special caps) can offer a much wider variety of caps, than only 30. Any of the 30 logos could be paired-up with any of the other 29**, for a total of 870 different caps. (EDIT: that number is erroneous, as explained in an annotation. Actually there would be 435 different caps.) Your target market is anyone who likes baseball, the game, more than any particular baseball team. And "collect the whole set!" is what you try to get those customers to do. (That quantity causes this Idea to be Half-Baked, although for someone who has a favored team, only 29 caps might constitute a "whole set", all having the favored team as one of its two logos.)

When two teams meet to play a game, the proud owner of the appropriate cap wears it to the game. A favored team would have its logo displayed throughout most of the game, with the cap having the relevant side out. If the favored team loses, the cap- owner can quickly/discreetly invert the cap and now display the logo of the winning team, and join the festivities of the winners.

**Note that while two teams in different leagues (example: New York Yankees and New York Mets) may very rarely play each other, it is most certainly possible. Think "World Series".