The first time I saw a band member wearing multiple hats, it caught me rather off guard. Why would anyone do this? It turns out, though, that the rule is that, when one leaves the stands during a game, one also leaves behind one’s hat. Apparently, the band hats are great targets for mischief by opposing fans and band members. Leaving them with a buddy is, therefore, a wise thing to do when you need to take a bio-break during the game.
So the other two hats are your friends’ hat. That makes sense otherwise, why would someone wear 3 hats at the same time.