Update: Aug. 28:
No, baby, Adam LaRoche's fly ball off the top of the scoreboard railing Sunday in Philadelphia PA was not a homer. Jayson Werth, of all people, should have known better. Surely, all of these players experienced "ground rule" issues playing neighborhood ball as boys. As kids, when we made our back yards into "stadiums", we argued over ground rules all the time. Some kids didn't realize that a ball caught on a carom off the wall (like the brick side of a house) without hitting the ground is not an out. We often used shrubbery hedges as outfield fences. Was a ball that grazed the top of a hedge a homer or a ground rule double?
Last picture: Minor league ballpark in Richmond, VA.