BOO ruling in Dizzy Dean

[greymule]

"I recall one where a coach was caught not playing a child who was not very talented. He walked in a run in order to avoid a slaughter rule just so the kid could bat in the fifth inning."

If I'm reading this correctly, I don't see where the coach is some sort of villain. I assume that the league requires that every kid play in the game (and bat). So the coach could have been planning to play the less-talented kid from the fifth inning on but then became faced with a shortened (4-inning) game, so he extended it to get the kid in. Yes, it's ridiculous that he had to walk in a run to prolong the game and satisfy the rule, but should a coach have to play every kid in the first few innings just in case the mercy rule shortens the game?