I, too, have never had this problem either, everyone is always overly generous rather and overly honest! But if you really don't trust the person you can set the box to like 100 lindens, and have the other person do the same, that way if the person doesn't give you the box they were supposed to would loose 100 lindens, and you would get 100 lindens for the box. Or something, I dunno. But honestly, I've never had this problem, at all, especially not within kittycats