ApexPC:
A lifetime scoring average is pretty useless, unless it's a lifetime that has a short span.
Though WGT doesn't use a handicap system, the USGA does. USGA's handicap is based on the 10 lowest of the most recent 20 reported scores.
The only thing different that the RIGA does, and I couldn't state in all certainty that the USGA also does, is that all Tournament scores stay with you for a full year. In the case of my RL CC we also have big 3 and 4 day member/ member comps and a 3 day member guest. All three have large purses, the biggest being a free membership to the winners, so for the sake of fairness if a person with a 10 HCI wins, the following year when they defend their title, they are chopped 2 shots.
Some don't like it, but it does stop sandbaggers from repeating year after year, and is only a local rule
The thought of 500 scores averaged for a true HCI is absurd.