[EricH]

Originally Posted by Manny A

It may be that they just wanted to penalize runners for doing something dumb, but not wantonly intentional, that hinders play. For example, runners at first and third, one out. Fly ball to right field, and the runner from first, thinking there were two outs, takes off for second without tagging up. She rounds second going for third when she hears her base coach telling her to go back to first base. So she takes of directly from the shortstop area back to first without thinking about retouching second base on the way. The right fielder catches the fly ball as the runner from third base tags up and tries to score. The throw comes in, and it hits the runner going back to first base somewhere between the pitcher's circle and the bag.

I can see where that runner should be called out for interference. Did she do something with intent to interfere? No. But did she run the bases in a legitimate fashion per the rules? Not really; she failed to tag up on the fly ball, and then she failed to return to first base properly by not retouching second on the way back. She basically put herself into no-man's land, and subsequently got hit with the throw. She had no business being where she was, so although she didn't do anything intentional, she did interfere with the throw home.

That's a good example.

Also this from the March 2007 rules clarifications:

SITUATION 3: With no outs and R1 at 1B, B2 hits a ground ball to F6 who fields the ball and throws to F4 at 2B to start a double play. F4 steps on 2B and throws the ball to F3 in an attempt to retire B2. R1, knowing they are out, turns to go back to the dugout where the ball strikes them in the back and ricochets into foul ground. RULING: R1 is guilty of interference after being declared out. In this case, because B2 is the only runner and therefore closest to home plate, B2 is also be declared out. (Rule 8, Section 7 J [3])

This one is interesting because I think a lot of umpires would let play continue with no call of interference.