I need some opinions on this.The old ground ball to second or shortstop with a runner leaving first or second crossing.On the play I just had the runner at first gets in front of the secondbaseman just as the ball is coming and sort of tiptoes and appears to screen her a little and goes by.The ball bounces off the girls glove and everybody is safe.The runner never stopped and only appeared to be avoiding the ball so since I was by myself I let it go.At what point do the rest of you call that interference?

The runner is crossing in front of the fielder. If the runner stops, or slows down to put herself in front of the runner I probably have interferance. If the runner is just running to the next base, and doesn't do anything unusal or out of the ordinary, there is no interferance, IMO

Bob is correct here. If all she was doing was checking-up to avoid being hit by the ball and the ball passed her prior to her passing the infielder, it is nothing.

From the scenario above, I don't quite get whether the runner waited and then crossed in front before or after the ball passed. If the runner checks-up and then passes in front of the fielder just before the ball reached her, that would be interference, "in my judgment."

Good comments above.
Plus remember this, "You'll know it when you see it." ;)
mick

For Mike I would say she checked up as you say.I couldn't say she purposly stopped which by the responses is what everybody looks for.So as was said here you will know it when you see it.