alosso & burchell - I believe we're addressing two different issues. One issue is not allowing people to play solo and force them instead into playing in groups of 2-4 players. The other issue is people who have a single account and people who have multiple accounts.
If you play as a single to pump up your average, you hurt no one. The OP did complain about the low averages as if they are a problem.
If your average is 54, your opponent knows that when a match is accepted. If you can't shoot that 54, whatever you actually shoot provides a window of additional opportunity to that opponent. If you shoot 56, 60, or 65 and win, congratulations. You are that good in match play against an opponent. Your single play the OP wishes to outlaw has absolutely no bearing on that result.
As I suggested before, what the OP should be looking for is single play tournaments. People in those are going to shoot higher scores than their averages since there is no restarting allowed after a bad hole. He should be prepared to see scores that are not that much higher, though. The good players really are that good.
I do agree that there are a ton of suspects in the lower ranks. I don't play for credits and a large part of that is the huge amount of account fraud here. People who started a new account to take advantage of using their Legend and above skills at a lower tier aren't going to be curbed by being forced to play rounds with other people. They have the superior skills already and aren't going to care as long as they still stand to be rewarded with credits for starting a new account.
WGT should lower the ability of anyone at Master or lower to gain credits in RG, monthly/weekly tournaments and betting play dramatically. Eliminate the credit prizes and restrict bets to something like 25 credits until they reach Tour Master and above. Restrict Tour Master betting too if need be. Increase prize payouts even more dramatically for Legends and TL players and take restrictions off betting for them.
Stop the multiple accounters by removing their incentive for starting a new account. Give low-tiered players a substantial goal to work for. Make people aspire to become Legends and TLs., not the other way around.