|Porter, PIT Manager Clint Hurdle and Layne discuss the play.|
Video: Snider's RBI double is technically upheld, though the rationale was changed to interference
Animated GIF: Alternate angles of the reviewed double, ruled fan interference (Compressed size)
As explained in Ball Boy Interference: Judging Intent of Non-Team Persons, Rule 3.16 authorizes umpires to "impose such penalties as in his opinion will nullify the act of interference." Meanwhile, Rule 2.00 [Interference (d)] was modified prior to the 2013 season, with the emphasized text added: "Spectator interference occurs when a spectator reaches out of the stands and over the playing field, or goes on the playing field, and (1) touches a live ball or (2) touches a player and hinders an attempt to make a play on a live ball."
As for the fan guilty of interference, PNC Park's A-Z Guide portrays a "zero tolerance policy regarding fan interference with a ball in play or a player during the game," specifying immediate removal from PNC Park and/or criminal sanctions as possible penalties. All other MLB stadiums have similar policies.
When Joe West ejected Phillies Manager Charlie Manuel in 2011 (Ejections: Joe West 7), it too concerned spectator interference; after review, the offending fans were accordingly ejected from the Florida ballpark.