Cheating happens, and it changes the sport you play. Look at premiership football, the amount of dives is unbelievable.
This next comment is slightly irrelevant, but back in sixth form me and friends used to play ****head (a card game), in which we adapted it so we had to cheat as much as we could to win. The only rule was if you got caught you got punished, but when you won; all bragging rights were yours. This evolved a fairly basic and boring card game into something more exciting, which can be seen to be similar in paintball.
When it comes to tournament paintball however, i can safely say i have never actually cheated during a tournament. Sure, i've had a shot to the pack i genuinely didn't feel, and i've been pulled for it, but there's not a lot i can do about that. But when everyone else is cheating, the sport adapts with it and changes accordingly. As people before have said, if they're breaking banks to be there and they get shot on the break, they have two choices;
1 - Rule #5 and get better at running
2 - Wipe, Enjoy your day, and make the most of it.
I don't agree with 2, and generally stick to 1. But when the sport becomes as competitive as it is, there will always be those who will fight and continue to act like this so their team wins. That's sport.
I can however say i've cheated at big games. North Vs South for example. I paid an arm and a leg in tickets, transport, paint, food, tent equipment etc... And i get hit in a woods in the middle of nowhere and i'm given the choice; Walk for 15-20 minutes to the nearest spawn point and run the risk of never seeing my team/friends for the entire game, or take a few yards back behind a tree or bush, wipe off, and enjoy the rest of my day with my friends, with no direct consequence to the guy who shot me; compared to the impact it would have on a tournament game.