This reminds me of the effect computerized ranking schemes for playoff berths had on the sportsmanship of high school coaches. When it became possible for a team with an N-0 record to miss making the playoffs because it had not beaten its opponents by a sufficiently high score, winning coaches had an incentive to keep their starting players in blowout games in an attempt to maximize the score differential. Without this rule, there was a tacit agreement that, after some threshold, lesser players would be substituted by both sides. As I'm no athlete, I don't know what the convention (or signaling mechanism) was, but the result was usually a swapping out of players on both sides within just a few plays.