The governing body of the MLB umpires, whatever it is called, actually discussed these types of issues after the Jeffery Maier incident. They concluded that it would be best for baseball to try and get the call right, therefore they are in favor of in-game conferrences regarding calls on the field. In that same game they met and ruled on the Bellhorn homerun that hit the fan and bounced back into the field of play. That wasn't initially ruled a homerun by the left-field umpire, but the right call was made after the conferrence.