In our modified league, you can't leave the base until the ball leaves the pitchers hand. That being the case, I don't see too many guys who actually steal the base, rather than advance on a passed ball or wild pitch. If you happen to be able to tell when the pitcher is throwing a change up and go, that's one thing, but if you're really waiting until he releases it and he throws with any kind of speed, you'd better be pretty fast. I'd rather just wait and see if it gets by the catcher.