Who needs more bosses?
Most kids really want to do the right thing and they want everybody else to do it too. The problem I most often see is how they try to get what they want. Kids are a product of their environment and they are always being told what to do. Their parents, teachers, bus drivers, older siblings, other kids, etc. are constantly giving direction. It's tiresome. I'd hate it if I had that many people telling me what to do. In fact, one time, I was walking into the kitchen to do the dishes and my wife told me to do the dishes and my gut reaction was "NO!"
Adults don't like being told what to do (albeit, I'm sure there's a small sub-section of society this rule doesn't apply to but there might be bigger issues there). Why should kids be any different?
My solution occurred to me one night as I was driving home. A passing car flashed its lights at me. My headlights were on, so they must have been indicating police ahead and I checked my speed. I wasn't speeding but I was thankful that the other driver was looking out for my well being.
In my PE classes, most problems start by somebody "forgetting" the rules. Generally speaking, kids are forgetful and get too into the activities and forget. Reminding them the rules helps them. Sometimes they're breaking the rules to gain an advantage. Some might call it cheating, but that's a forbidden word in my gym. Kids are smart, and wily. They will test the limits and see what they can get away with. They'll see if anybody notices. Then they'll see if anybody has the stones to do anything about it. They'll find loopholes and ways to work the rules into their favor. Sounds like just about every successful person in the history of the world, if you ask me. If they're using the rules to their advantage, that's great! Isn't that what we want our kids to do? If they're intentionally breaking them to gain an advantage, that's what we don't want. But if you call them out on it, or call them names (such as "cheater"), they get defensive. Then, they either act like they didn't do it, say they forgot (or didn't know in the first place), or bring to light another problem they see somebody else doing. But, instead, if you "assume the best" out of them, you'll typically get the best out of them.
My steps are simple. Just remind them the rules and be calm and kind (because nobody really cares what anybody says if they're yelling or angry). And I do the same thing. I try not to be in charge of kids or tell them what to do (believe me, it's a work in progress; especially with a couple toddlers at home). When I see kids who are blatantly "cheating" and I just calmly remind them the right thing to do, they do it. I've seen it work great when my students do it as well.
Pro Tip for the kids: if you have to remind somebody more than a couple times, remind them loud enough for somebody in charge to hear. You're not telling on them, you're clearly helping them, and you get the added bonus of bringing an adult's awareness to a problem they might not have noticed. It's no different to me getting loud on the street if somebody is harassing me and I want to draw more attention to the problem.
Here's a little video of my teaching this skill to my Kindergarteners (the clown faces are to hide their identities).