Third Base Stealing Home

Of course he can. After ball four, the ball is live in the major leagues, minor leagues, college leagues, high school leagues, junior high school leagues, and in many of the lower kids' leagues.

I have coached kids teams where they ran the same play. In fact, in a league where runners could not leave the base until the pitch reached home plate, one coach we played against had his runners taking second on walks all the time, trying to draw a throw to second so the runner from third could score. In that league, runners could not leave their base once the pitcher had the ball and was on the mound, but his runners were already past first before the pitcher got back on the rubber with the ball.

The film would have been ridiculous if they had Billy's team doing this over and over, as other teams would easily counter it if they expected it. But as a one-time surprise move, it could even work in the big leagues, the same way you occasionally see a hidden ball trick work--I saw one last season.

Yeah, perfectly legal. Until the ball is thrown back to the pitcher the runners may advance as far as they like. Usually the ball is thrown back immediately though so something like this would most likely never happen.

Yes indeed. The rules of baseball don't change from little league all the way through the bigs. When a batter is walked he can walk to first base, stop or keep going.