Should you hide the gun of a drunk who plans to go shooting, even if you know he'd hurt no one but himself? Does he benefit from your taking his guns? Is it a violation of his rights? What about emptying a bottle of a dangerous snake-oil medicine your mother plans to take, cutting up your wife's credit card, or surreptitiously shredding the check of a friend about to make a bad investment? When would forcible intervention in such cases be justified, if ever? When would such intervention genuinely benefit the person, if ever? When would it violate his rights?