I disagree and I'll tell you why. The best bands are good from the bottom up. Almost all bands are good from the top down. Your very finest ensembles are the best not because of the top players, but because of the bottom players. Making players change parts, and putting them on the top parts even though they are not a top player says to them, "here is your part and it is your responsibility to make certain it gets played." Putting better players on lower parts makes the statement that all parts are important, not just first parts. It also makes a loud and clear statement that no member of my band is more important than any other player. We work as a team, we function as a team, and we perform as a team. We are only as good as our worst player, so if you are better than someone else it is your responsibility to make that person better. At my school there is never a time to worry because the first chair player can't come to a concert because he/she is sick. Why? Because we don't have a first chair player. All solos are doubled, so even if a soloist is ill we have a back up. In rehearsal the solos are played half by one player, and half by another player. We even practice where one player plays and stops and the other player picks the solo up half way through it. We do this incase the player gets so nervous the solo falls apart, or incase a valve sticks and the soloist can't continue. At my school, nobody beats another person in a "challenge"; instead they take on the "challenge" of making all of our players good players. There is no incentive to not want the player "behind you" to get better, but instead the attitude that if any single player improves the entire ensemble improves.