Accidental appeal and mechanics question.

[JJ]

When I went to umpire school MANY years ago I was taught to signal "safe" because the batter-runner beat the throw, which was the play beinig made on the batter-runner. If the defense then appealed that he missed first, I was to rule on that "play".
Times have changed, but I still call it that way, and will until a higher authority tells me otherwise.