(a) One run shall be scored each time a runner legally advances to and touches first, second, third and home base before three men are put out to end the inning.
EXCEPTION: A run is not scored if the runner advances to home base during a play in which the third out is made (1) by the batter-runner before he touches first base; (2) by any runner being forced out; or (3) by a preceding runner who is declared out because he failed to touch one of the bases.
Rule 5.08(a) Comment (Rule 5.06 Comment): A run legally scored cannot be nullified by subsequent action of the runner, such as but not limited to an effort to return to third base in the belief that he had left the base before a caught fly ball.
(b) When the winning run is scored in the last half-inning of a regulation game, or in the last half of an extra inning, as the result of a base on balls, hit batter or any other play with the bases full which forces the batter and all other runners to advance without liability of being put out, the umpire shall not declare the game ended until the runner forced to advance from third has touched home base and the batter-runner has touched first base.
Rule 5.08(b) Comment (Rule 4.09(b) Comment): An exception will be if fans rush onto the field and physically prevent the runner from touching home plate or the batter from touching first base. In such cases, the umpires shall award the runner the base because of the obstruction by the fans.
PENALTY: If the runner on third refuses to advance to and touch home base in a reasonable time, the umpire shall disallow the run, call out the offending player and order the game resumed. If, with two out, the batter-runner refuses to advance to and touch first base, the umpire shall disallow the run, call out the offending player, and order the game resumed. If, before two are out, the batter-runner refuses to advance to and touch first base, the run shall count, but the offending player shall be called out.
Rule 5.08 Comment (Rule 4.09 Comment):
APPROVED RULING: No run shall score during a play in which the third out is made by the batter-runner before he touches first base. Example: One out, Jones on second, Smith on first. The batter, Brown, hits safely. Jones scores. Smith is out on the throw to the plate. Two outs. But Brown missed first base. The ball is thrown to first, an appeal is made, and Brown is out. Three outs. Since Jones crossed the plate during a play in which the third out was made by the batter-runner before he touched first base, Jones’ run does not count.
APPROVED RULING: Following runners are not affected by an act of a preceding runner unless two are out.
EXAMPLE: One out, Jones on second, Smith on first, and batter, Brown, hits home run inside the park. Jones fails to touch third on his way to the plate. Smith and Brown score. The defense holds the ball on third, appeals to umpire, and Jones is out. Smith’s and Brown’s runs count.
APPROVED RULING: Two out, Jones on second, Smith on first and batter, Brown, hits home run inside the park. All three runs cross the plate. But Jones missed third base, and on appeal is declared out. Three outs. Smith’s and Brown’s runs are voided. No score on the play.
APPROVED RULING: One out, Jones on third, Smith on second. Batter Brown flies out to center. Two out. Jones scores after catch and Smith scores on bad throw to plate. But Jones, on appeal, is adjudged to have left third before the catch and is out. Three outs. No runs.
APPROVED RULING: Two out, bases full, batter hits home run over fence. Batter, on appeal, is declared out for missing first base. Three outs. No run counts.
Here is a general statement that covers:
When a runner misses a base and a fielder holds the ball on a missed base, or on the base originally occupied by the runner if a fly ball is caught, and appeals for the umpire’s decision, the runner is out when the umpire sustains the appeal; all runners may score if possible, except that with two out the runner is out at the moment he misses the bag, if an appeal is sustained as applied to the following runners.
APPROVED RULING: One out, Jones on third, Smith on first, and Brown flies out to right field. Two outs. Jones tags up and scores after the catch. Smith attempted to return to first but the right fielder’s throw beat him to the base. Three outs. But Jones scored before the throw to catch Smith reached first base, hence Jones’ run counts. It was not a force play.