I'm sort of guilty of this. There were one or two shirts I always wore to my son's HS games. Even had a tattered hat with the HS logo that I always wore. I did have my "spot" where I stood to watch the game, but I refrained from dragging other parents into wearing the same clothing, etc.
Overheard at a 12u game:
"Man, can't you wait to go to the bathroom until the other side is up? We almost had a homer but YOU weren't in your spot so you jinxed us with a pop-fly!"
Sadly, these grown men were actually serious.