Maier, Bartman and Vernick by Havelock Hewes

   The answer is "Jeffrey Maier, Steve Bartman and Bill Vernick." The question is "what three fans decided the outcome of a game by touching a live ball?"
  During a playoff game at Yankee Stadium on October 9, 1996 Derek Jeter hit a long flyball.  Tony Tarrasco, the Oriole outfielder, settled under it in right field, when 12-year-old Jeffrey Maier reached over the fence and had the ball bounce off his glove into the stands.  The umpire, Rich Garcia, called it a home run, allowing the Yankees to win the game.
  During a playoff game at Wrigley Field on October 6, 2003  the Cubs had a 3-0 lead and would be in the World Series if they could hold on.  In the 8th inning, the Marlins batter hit a flyball to right which was drifting toward the stands.  Moises Alou, the cub outfielder, reached up to catch it, but Cub fan Steve Bartman put his glove out in front of Alou's, and, in an attempt to catch the ball, had it ricochet off his mitt.  The Marlins went on to score 8 runs and dash the Cubs attempt to get to their first World Series "since the year we dropped the bomb on Japan."
 During game one at PS 141, on Monday, September 1, 2014 Havelock Hewes' team scored five first-inning runs.  During one of the early innings a fan, believed to be Zach Nilva's father, standing in the gate behind firstbase retrieved a live ball.  The umpire, Havelock Hewes, awarded the runner at first, second base.  At this point he announced "the rule for this field will be 'if any spectator touches a live ball the runner will be awarded one base'"  In the bottom of the seventh inning, with the score now tied, the hitter for Freddy Melendez' team singled and the ball briefly eluded Havelock and rolled past first.  Havelock trotted over to pick up the ball, when spectator Bill Vernick picked the live ball up and tossed it to Havelock.  Freddy, now umpiring, enforced Havelock's rule and awarded second to the runner. The next batter singled and the runner scored from secondbase to win the game.
  "Hoisted on my own petard," Hewes mused after the game, "At least Bill has better hands than Maier or Bartman."