Brother Jerry is right regarding the arms race starting long before sport paintball. I don't however accept the claim that the sport side brought cheaper paint, markers or greater marker diversity. Sales volume brought lower prices and sport paintball begat double triggers on everything and tournament regulation standardization which is less diversity any way you slice it.
Regarding the cheating, it goes to incentive. In a game of honor amongst friends there is little incentive to cheat and much to not cheat. The very opposite is true in sport. The incentive to cheat is particularly potent in sport with cash purses, sponsorship and publicity. You can debate that all you want but you know I'm right.
I tend to call myself out on a hit that doesn't break when I play. If I'm hit and the ball didn't break I can exploit the technicality and stay in the game or I can congratulate the other player on a nice shot and leave the field. I know which is the right thing to do... Unless there's money and fame at stake.