I'm not really sure when it started, but it appears the Angels might be using subtle mind games on their opponents.
During Tuesday night's Angels - Oakland game, I thought I remembered reading about a college football team painting the vistors' locker room pink in order to give the home team a slight edge in the "manliness" department. After a little research, there indeed was a college team, the University of Iowa, had employed the color pink to give themselves a greater home field advantage. Per Wikipedia:
Kinnick Stadium is well known for its pink visitors' locker rooms, a tradition started by emeritus Iowa coach Hayden Fry.