Rule Trivia

[youngump]

Originally Posted by MD Longhorn

What about the fact that when the play is over we are to announce the obstruction and award the runnerS (plural) the bases they would have achieved had there been no obstruction.

Had there been no obstruction on the runner, she would have made it back to 2nd before the BR got anywhere near there. We cannot and should not assume BR would have been put out - it's much more likely she simply returns to first.

I don't think that's what's meant. What we're asked to do is not piece the play together completely as if there had been no obstruction but to determine who did something different because of the obstruction.
In this play, R1 is going to be back at second safely absent the obstruction as determined at the time of the obstruction. Therefore, BR is not going to get second absent the obstruction. If R1, realizing she has been obstructed decides to try for 3rd, the BR may decide to advance to second. But she is certainly not protected in doing so despite the fact that absent the obstruction she does not attempt to take the base.
Now, it's likely instructive to consider a case where the runner being obstructed clearly does make a difference to BR.
R1 is obstructed coming around second on an obvious double to left field. Realizing she can't make third now and unaware the umpire saw the obstruction she returns to second causing the BR to return to first. After the play award both runners an extra base.
Is your case more like my second or my like the first? I'd say more like the first. Yes, had R1 not been obstructed it is possible that BR would not have made the same baserunning mistake, but it's too much of a stretch for me.