I don't see why they should be allowed to advance a base.
Yeah...I wondered about that also. The only thing I could think of is that they want to make the team in the field pay a price for falling into the dugout to prevent it from happening (I imagine to cut down on injuries).
I guess they see it to be similar to when a player throws the ball and it leaves the playing field. The players advance one base in that instance, too. In bot situations, the player is responsible for the ball being taken out of play.
Is it considered to be a homerun if an outfielder falls into the stands (in fair territory) while catching the ball? I don't think so, but I'm not sure.
So they're telling the players not to play all out? Play hard and we'll advance the runners so just dog it.
That's gonna get ugly. Hit the ball 50 feet and get a sacrifice fly for a run? Every starter in the league just saw his era jump a half a point.
This is dumb. Why should a team be PENALIZED because its player hustled? I don't want infielders having to stop and THINK about whether or not to run after a foul ball!
I suspect this may be a way to discourage players from leaping into places that could cause injuries. Also, there is the potential for a "lack of consistency" in the results of a play in two respects: 1) depending on whether a player chasing a ball into the stands is from the home team or visitor's team; and 2) depending on whether a player chases a ball into his own team's dugout or the opposing team's dugout.
They are carrying the ball out of play and it is assumed the runner may have tagged and advanced. Assumption in favor of the "non-offending" team.