This is true, but a player playing for a birdie on a par 7 is going to play different than a player playing for a birdie on a par 5. They might choose not to bring as much risk into play and just chip away at the fairway a few times. So while they are playing the same fairways, they are attacking them differently. A player capable of getting a 5 on hole 5 for instance might play for a 6 on purpose, just to guarantee themselves a handicap par birdie.
That's called course strategy, and handicap is not ratings, and has nothing to do with DG. In the performance flight, you still have to play the best round you can, which ultimately means the lowest score you can card, regardless of strategy.
Sure it does, but they're not doing it because they don't care. High numbers are going to happen at Winthrop no matter what side of the field you're on, but you might get a lot more instances of high numbers from the performance flight if you get someone that knows they're not going to get the trophy and they're just there to have fun so they start bringing on unnecessary risk. The game you play when nothing is on the line is different than the game you play when money is a factor.