With young ones with really stupid ideas, (if possible) I’ll give them 10 minutes of “free time” where they are off the line and can do whatever they want, as long as it’s a trot or faster. I’m not going to goose them into being stupid, but if they want to they’re free to.
I don’t allow screwing around on a lunge line - no bucking, no rearing, no raring around.
I find the horses need the free time when the footing outside is not conducive to a good buck-fart-roll - too muddy, too icy, whatever. It gets all built up and they can’t figure out how to contain it. 10 minutes once a week or so, and they’re able to reinstall their brains and work a little.