[Blue37]

OBR 7.06 When obstruction occurs, the umpire shall call or signal "Obstruction."
(a) If a play is being made on the obstructed runner, or if the batter runner is obstructed before he touches first base, the ball is dead and all runners shall advance, without liability to be put out, to the bases they would have reached, in the umpire's judgment, if there had been no obstruction.

(b) If no play is being made on the obstructed runner, the play shall proceed until no further action is possible. The umpire shall then call "Time" and impose such penalties, if any, as in his judgment will nullify the act of obstruction.

Both (a) and (b) give authority to place the other runners, but you must be certain the obstruction affected the other runners.

Situation: Runners on 1st and 2nd. Batter hits one to the fence in right center. F5 obstructs R2 as he nears 3rd. The contact stuns R2 to the point he cannot advance past 3rd. As a result of the obstruction, R1 has to stop at 2nd and the batter has to stop at 1st. In your opinion, absent the obstruction, this would have been a stand-up triple with two runs scoring.

7.06(b) says to "impose such penalties, if any, as in his judgment will nulify the act of obstruction." In the above situation, my judgment is to score the two runs and put the batter on 3rd.

In the original situation, if I saw the batter check up due to the obstruction of R1, and I was certain it was the check up that cause him to be out at 2nd, I would place him on 2nd.