USTA League tennis works out great for the vast majority of players. They get to play competitively in a team environment against others at or around their skill level, and a few get to move on and experience playoffs and championship play. This works great at the 3.5 and 4.0 levels where there is a large pool of players in most sections and districts.
When you get to the higher levels though, there are fewer players and thus smaller leagues and in some cases not enough players to field teams and leagues and thus these players may not have the opportunity to play USTA League. This typically happens at the 5.0 to 5.5 level.
In an effort to give these players more opportunities to play, the USTA established "plus" leagues this year. In the 18 and over division you may see 5.0+ leagues and in the 40 and over, 4.5+ leagues. A plus league allows a team to roster two above level players (two 5.0s for a 4.5+ and two 5.5s for a 5.0+) with the stipulation that they must always play court 1 singles or doubles. The idea is that this allows these players to play in a league they otherwise wouldn't be able to but still ensure that the 5.0s are playing each other so they both have a competitive match.
The problem arises when there is a team (say team A) that doesn't have two or perhaps even one 5.0 (we'll use a 40 and over 4.5+ example) rostered or available for a match while their opponent (team B) does. If the captain of team A knows team B is bringing their 5.0 and he's a singles guy, he may not want to put his best 4.5 singles guy up against him as it may be a likely loss, so he plays his 4.5 singles guy at court 2 and runs out a weaker player, perhaps even a 4.0 playing up, at court 1.
The result is the court 1 singles match is an uncompetitive match and team B's advantage of having a 5.0 has been reduced as team A is playing their best players/teams on the 4 other courts and just needs to win 3 of them. Worse, by having to play a weaker player and like I said, perhaps a 4.0 playing up, the 5.0 is in a no win situation with respect to maintaining his NTRP rating. Unless he wins 6-0, 6-0, there is a good chance his rating will go down just by showing up and winning easily. If this happens several times, the 5.0s rating could drop significantly and result in him being bumped down at the end of the year.
Certainly this is an unintended consequence of an otherwise good intentioned effort to increase opportunities to play for higher level players. There is no way to mandate or ensure each or neither team has their 5.0 (if they have any) players at a given match, and there are no rules about who has to play on which court if they aren't a plus player, so this situation is inevitable.
One way to mitigate the situation would be to require a team to play their stronger players on the lower numbered courts. But unless the USTA is going to publicize the Dynamic NTRP ratings to the hundredth, there is no way for a captain to know who is really stronger or to police it. However, a rule that could be put in place is that a player playing up cannot play on a lower court number than an at-level player. This would ensure that a plus player never has to play someone 2 levels below them, unless the opposition runs out nearly a complete line-up of players playing up.