Look back rule question

[Dakota]

Where I've actually seen umpires call this wrong is either

1) They do not believe the runner CAN round and stop on a walk after F1 has the ball in the circle and will call the out if she does not continue on to 2B once she rounds, or

2) As the OP stated, they will "give" the runner a couple of steps, and beyond that consider her committed to 2B without stopping. So, she will be rung up if she takes, for example, 4 steps instead of 2.

No sensible runner is going to go to within 1 inch of 2B and then return, but it is the extreme example used to teach the proper rule application.