[greymule]

So on the two-out bases-loaded game-winning home run with the score tied, if the runner from 1B misses 2B, he can be called out on appeal and the run will be nullified because that's a force play. If he does not miss second but simply fails to advance and touch it, that's not a force play, and the run scores as long as R3 touches home and the batter touches 1B.