Swampboy posted:In your first situation of a batter interfering after swinging and missing on strike 3 while a runner is attempting to steal second, the batter is already out because he struck out. Let the play unfold. If the runner is put out, the ball remains live. If the runner is not put out, kill the play and decide whether to return the runner to first (if you think he would have stolen the base without the interference) or call him out (if you think he would have been out).
If the interference prevented a double play, get the second out. If it didn't prevent a double play, return the runner. How do you tell? If it's a good pitch to handle and the runner has no better than a normal jump, I'll get the second out. If it's a hard pitch to handle and the runner has a noticeably good jump, I'll return him. In between, I do the best I can. Again, the goal is nullification, not punishment.
Swampboy's post applies only in FED. Under NCAA and OBR, the runner is out no matter how you judge the steal attempt.
And, FWIW, I have a higher standard before returning the runner that how I interpret Swampboy's standard. A guideline would be to get the out unless R1 is stealing on the pitch and the ball gets away from F2. If F2 has any kind of a play on R1, get the out.
Finally, the rule on the "follow-through interference" is also different between FED (it's just another kind of BI) and NCAA / OBR (it's "weak interference" and return the runner unless the runner is retired on the play).