Discipline is all about choices and consequences. I'm a teacher by training so I'm big on positive reinforcement. Gotta catch the kid being good and reinforce it. My kid's elementary school uses a positive reinforcement system, too. In kindergarten, the kids earned stars that could be redeemed for a small prize (like an eraser or a bracelet). In 2nd grade, the kids earned cards (animal cards, I think). My kid was named a "star" for his good behavior and he got his picture posted in the cafeteria. All of this stuff is a big deal to the kids. So much of the time, the teacher has to spend time correcting disruptive students and the well behaved kids don't get the same attention. The positive reinforcement system gives the well behaved kids a good consequence for their behavior.
According to the experts, you're always supposed to give the child choices. Lately, my teenagers choices are "do your homework or I'm going to kill you!" LOL!