Ground rules - whose responsibility to establish
 

We played on a field yesterday where the dugouts were sunk into the ground. The concrete front edge of the dugouts stuck up about a foot above the foul territory infield surface. There were poles and a chain link fence immediately in front of the front edge of the dugout to protect the players in the dugout. There was an opening with no gate or fence where the players entered and exited the dugout. While our team was on defense, our first baseman missed a throw from another infielder. The ball rolled toward the dugout and bounced off of the portion of the dugout wall extending above the foul territory infield surface. The batter/runner was safe at first but the home team coach came out and told the umpire that the portion of the dugout wall where there was no fence or gate was dead ball territory and the runner should go to 2nd base. This was not mentioned at the pregame conference. Does the home team establish ground rules or is this done by the umpiring crew after arriving and inspecting the playing area?

The home coach makes the ground rules for the field and they should have been gone over in the pregame meeting. But, ground rules cannot supersede book rules.

If not mentioned in the pre-game and is not covered in the regular rules, it doesn't exist.

A wall, fence, whatever, facing the field and used as an enclosure to keep a ball in play should not be considered DBT. There are obviously some exceptions such as the back wall of an open dugout or the like, but that would be a case where the ball crossed a DBL prior to hitting the wall. I'm having a difficult time envisioning the edge to this dugout and if it is possible for the ball to get lodged or come to rest where a player does not have immediate access to it, that could be an exception, but should obviously have been covered in the pre-game

And the umpire defines the DBL if the home coach does not or, as in travel ball, there is no actual home coach.

Good basic point - "an enclosure to keep a ball in play should not be considered DBT"