Thinking outside the box is good. Holing a 40 foot put is not standard, and not really relevant.
Not all greens or all pin placements will be bad, but you should have situations where a decent put that misses by and inch, and has a foot extra speed to pass the hole, ends up running a long way...
Make courses tough by having narrower fairways, and trees nearby. Punish for being wayward off the tee.
Making them tough by adding a crazy-golf green is crap.
Right, so is the 2 shot penalty (as Phil got) specifically in the rules for deliberately hitting it when you know it's moving? That's a weirdly light penalty for deliberately cheating.
Presumably that's for when you're about to hit the ball, and it moves, and it's not intended to cover doing it deliberately to stop your ball running off the green?