[greymule]

I still say one runner must physically pass the other in the base path. If R3 stumbles past 3B and falls 4 feet behind the bag, and R2 is advancing toward 3B, when does R2 "pass" R3? When R2 gets within 4 feet of 3B? If both R3 and R2 are scrambling to 3B, do we call R2 out when his distance from 3B is less than R3's?

To me, even if R3 retreats to 3B and continues 10 feet down the LF line, he's still on 3B for the purposes of being passed.

If R3, retreating, overran 3B and did not move toward 2B, I would not require a touch of 3B if he then proceeded home.

I would call plays according to these interpretations. Unfortunately, I see no case play in J/R, PBUC, BRD, or Annotated Rule Book, so all us arguing our conception of what constitutes "passing" is probably not going to accomplish much.