In the army deserters are shot. That stops guys trying to run away. I mean, it doesn't make sense to stay when you might get killed. So the IFBB employs a similar threat. Stray and you are gone.
A classic example of game theory used in evolutionary theory explains why trees are tall. Instead of needing all those resources to get tall it would pay all trees to be much smaller. If they cooperated and shared resources they wouldn't need to be tall. However, individual trees that were selfish and did their own thing grew taller. Thus, eventually only the tall trees had offspring and there you are. It pays to be selfish, especially over a long period of time.
Suppose you have 10 close mates and you go to this room that has 11 sound proof cubicles. Each person goes in a cubicle and closes the door. In front of each person are two buttons. One is Red and the other button is Green. A sign reads: You have 1 minute to decide and you can't communicate with anyone else. These are your choices. 1. press the Red button and you instantly get $10,000. 2. If everyone presses the Green button then everyone will get $100,000 each. However, if one person presses a Red button the others get nothing and the person who pressed the Red button gets $10,000. The question is, what button do you press and how does it take you make your decision?