3 part question 1 of 3
 

How would you handle the following situation? Boys MS 7th grade followed by 8th grade. I arrive at the gym at the basket can not be lowered. So the AD decides to play cross court. There is no center line. The one end line is at the wall. The bleachers are two feet off the other end line. Do you play the games or not?

Do the best that you can.

I never had to deal with something like that except for during the summer. And even thing we judge where the line would be based on how the court is drawn. No big deal.

Peace

7th/8th grade ball, make do with what you got. Varsity, that would be another story.

Is there a liability issue with the wall being OB. If someone were to get hurt would the referees be liable?

If you are that worried about the safety, do not play the game. But I would not think you would be much more liable than the people that want to play under those conditions.

Peace

Make your imaginary restraining lines and play the game.

There are provisions in the rules book for handling gyms in which there is not at least three feet of space outside of a boundary. Namely, the temporary restraining line rule. The fact that there are such provisions in the rules tells me that the mere presence of a wall close to the court isn't considered a safety issue. There would have to be some obstacle or piece of equipment that could injury someone. Sure, players could get pushed into the wall while being fouled, but otherwise they are likely to control their actions and not crash into it.

As for the division line, here is what the NFHS has said to do:
1998-99 NFHS Basketball Rules Interpretations
SITUATION 2: A "bobcat, jaguar, wildcat, bronco, cougar, mustang, etc." logo was painted in the center restraining circle, with no contrasting 2-inch-wide dividing line in existence where the logo was painted. The referee permits play to begin without the dividing line being marked.
RULING: Incorrect. Play shall not commence until the visible midcourt dividing line is marked. (1-3-2)

SITUATION 3: A "bobcat, jaguar, wildcat, bronco, cougar, mustang, etc." logo was painted in the center restraining circle, with no contrasting 2-inch-wide dividing line in existence where the logo was painted. The referee permits play to begin without the dividing line being marked. The game is to be officiated by a three-person crew and the three assigned officials agree they will be able to accurately cover the floor, even without the visible midcourt dividing line.
RULING: Without exception, and with no consideration for uniqueness of design, play shall not commence until the visible midcourt dividing line is marked. (1-3-2)

2000-2001NFHS Basketball Rules Interpretations
SITUATION 16: The home team had its floor re-painted in the off-season with its school mascot painted in the middle of the floor. The mascot is painted over the division line, so that the line is obstructed and not clearly visible. RULING: There is no penalty accessed to the home team. Every effort shall be made by home management to place a line (temporary or permanent) on the floor. If a temporary line is placed on the floor, precautions should be taken with the substance used to minimize the risk of injury to players and officials. Every effort should be made to play the game. The official should notify the state association of the situation. COMMENT: If you are aware of a facility in which this could occur, contact your state high school association to determine how the situation should be handled in your state. (1-3-2)