The MLB rule is in plain view in every clubhouse-including Pete Rose’s clubhouse, right as he was breaking it-because of the 1919 Black Sox scandal.
Elsewhere in these ballparks are gambling signs of a different kind: ads and sponsorship logos for DraftKings, BetMGM, FanDuel, and the like. It says that any player, umpire, or employee of a team or the league who bets on a game they’re not involved in will be banned from MLB for a year if they are involved in the game, the ban is for life. In every Major League Baseball clubhouse, a sign with Major League Rule 21(d) is prominently posted.
