Golf in real-life is just as rife with a lack of true integrity with lower level golfers but they generally don't win many tournaments before they are discovered and the local club or regional golf association takes some sort of action. There are sandbaggers who don't post every score, others who intentionally inflate scores, others who take "gimmees" but still post, the five finger wedge, the foot wedge, etc. The biggest aid to catching them is the requirement that they play tournaments in groups where their competitors can catch them in the act.
The SCGA locally has taken disciplinary action in a number of cases where they have flagged tournament performances that are out of line with handicaps the players have established. Most local clubs do it before the SCGA even gets involved.
To catch many multi-accounters and those with illegal swing aids in this game WGT needs to add the ability to play in multiplayer groups in tournaments. Besides a cheater being caught using an illegal aid, cheaters are much more liable to slip up in chat about another account during the course of a round. Most of them will continue to play alone but that in itself becomes a flag if they NEVER play with anyone else. You're not going to catch them all but a dent could be put in it.