There's a discussion I was having with a guy at work about swear words. We teach kids not to swear at all, because kids don't know when it is and isn't appropriate to swear. Just like with learning anything, you learn the rules before you learn the exceptions.
In music, you learn which notes are in a scale before you learn when to play the notes that are not in the scale. Playing notes out of scale on purpose sounds good, but playing notes out of scale because you have no idea what you're doing sounds horrible. In martial arts, you learn the rules of your techniques, and then you learn when to break them. As a humorous recent example, in sparring the other day, there was a girl who accidentally kicked a couple of guys in the groin. I heard their complaints before I sparred her. So I fought her with my hands locked about six inches in front of my groin. My Master thought this was hilarious, and it turned out to be effective because she kept kicking low. In any other situation, letting my hands hang down instead of keeping them by my head would have gotten me in trouble (both with the Master, and with my partner kicking me in the face). So the "rule" of keeping my hands up was broken, but broken intentionally and with great effect. In another situation, I've seen a kid who was too lazy to keep his hands up, got kicked in the face like 14 times in one round. He broke the rule unintentionally and paid the price.
Coming back to this story, this guy knew the right timing of being a smart aleck. Kids don't. So the 8 and 10 year old that were watching him needed to see him get the pushups for what he did.
