I think there are laws against stealing because IRL we cannot control whether someone steals from us or not. However, in this case, "thieves" must ask before they "steal", giving the "victims" permission to grant or deny the "theft". First of all, wouldn't the victim actually be an accomplice in the theft, making the victim guilty as well? Secondly, the system we currently have is more similar to pressing charges. We don't have a law where the plaintiff must press charges for assault, but instead they have the choice to not charge at all.