In any recreational sport, there are players with varying degrees of skill, the full range from beginner to aspiring or former professional.
In golf there is a handicapping system where by a player enters their scores and the course/tees played into the system and a handicap is calculated. This number, very roughly how many shots over par a player may be expected to shoot on a regular basis, allows players of different ability to compete on an equitable basis.
For example, a player A with a handicap of 10 plays player B with a handicap of 6, player A will "get 4 strokes" in order to be able to equitably compare scores at the end of the round. In theory, two players of any skill set can play and have the playing field leveled through the use of their handicaps.
In tennis, we don't have a way for a near pro to play a beginner and have a level playing field, but we do have the NTRP rating system used by the USTA to rate players at several different standard levels, so that players of the same level can play and have competitive matches.
Of course, no system is foolproof or safe from being manipulated, and this happens with both golf and tennis. Some golfers choose not to enter good rounds because it would lower their handicap and they'd get fewer strokes, and some tennis players choose to throw matches to lower their rating so they can play at a lower level against weaker competition just so they can win. The fact that either of these occurs is unfortunate.
In golf, the handicapping system has some provisions built in to try to combat manipulation. For one, only your 10 best rounds out of your last 20 count towards your handicap. So unless you are going to throw a lot of rounds, the bad ones don't count and only your good rounds that reflect your capabilities will go into the calculations.
With the NTRP system, to my knowledge, there is no such omitting of results, but perhaps there should be. Further, some sections/districts choose to include or not various leagues and tournaments. This gives some players ample opportunity to use "secondary" leagues to throw matches and lower their ratings. If I were doing the system myself, I'd probably build in some checks to preclude counting thrown matches or throw out highs and lows in the calculations.
To be fair, the NTRP system does have year-end calculations where different matches are weighted more heavily, specifically those in playoffs and those played against players who played in the post-season. By doing this, the matches that players are likely trying their best in count more which makes sense.
And this is the time of year that these post-season matches are taking place, so these are the ones that will count the most. Good luck to all those playing in playoffs. Go out there and play your best and if you get bumped up, congratulations and embrace the challenge of playing tougher opponents next year.