I think it's kind of silly to think that social services would need to be called in. What an awesome way to teach your child a lesson! Parents now a days are too "soft" and worried that their kids won't like them. You're the parents and I think it's great! My mom sold one of my toys when I was young (6) because I broke a dresser. Fine by me, I learned to not play on my moms stuff anymore. No more sold toys, no more broken dressers. :)
Besides, it's toys. They'll get over it.