In Emmott's case, it was all his and Freeman's doing. He self-rated at 5.5, appealed to 5.0, and played in a non-advancing fall doubles league where he was (just coincidentally, of course...) only matched against 4.5s and lost every match like 6-2 6-1 (all while he was winning open level tournaments against 5.0 level competition at the same time). He got a 4.0 C rating from those league matches and (shockingly) showed up on Freeman's 4.0 nationals roster the next year and got double bumped to 5.0 C at the end of the year. That team lost in the finals to an even cheatier team from SoCal in the finals. It was one of the only times I was actually glad to see the cheatiest team win.
That SoCal had had (sampling):
4.0C who'd been a 4.0S the prior year and didn't tank (went 6-0!) to get the 4.0C, got the double bump and hasn't played league again
A 2012 and 2013 4.0 who got bumped up to 4.5 and has only played one more league match since (2016)
4.0S who had three losses at Nationals, still bumped up to 4.5 and hasn't played since
4.0S that went 1-1 at Nationals got bumped up to 4.5 and hasn't played since
2012 and 2013 4.0 who got bumped up and hasn't played since
A 2012 4.5 who got bumped down to 4.0 and then got bumped up again and has gone back and forth since. There were
a lot of lopsided losses in 2013, and then again in some subsequent years to the point of almost being a 3.5, but got back to 4.5 again after.
A 4.0 who was bumped up to 4.5 and stayed there for years, did appeal down in 2019.
A 2012 4.5 with lopsided losses in 2013 to get bumped down.
That is just a sampling, others look more benign. What is interesting is how many of these basically stopped after the 2014 championship.