Derby's under the law are covered under the attractive nuisance doctrine. This tort (short version) holds that the landlord is responsible for damages to children by a landlord's leaving unattended machines and such that children would be attracted to and want to play with. Under the law, all children are guiltless in the throwing of snowballs or in summer months small racks at those wearing Derby s or Top Hats. The cases first precedent was that of a T. Tim vs Ebenezer Scrooge, in 1843. Enjoy your derby, but also wear a medical alert bracelet.