Federal preemption principles did not preclude children of patron who died in single vehicle collision from suing riverboat casino under Dramshop Act; although sale and service of alcohol to patron occurred on vessel capable of transporting passengers on navigable waterway, there was no federal maritime statute comparable to Dramshop Act and no consistent or uniform body of maritime common law imposing tort liability on sellers of alcohol for injuries resulting from their sales, and casino carried dram shop insurance and secured its gaming license, as well as its authorization to sell alcoholic beverages, on condition that it would comply with state liquor laws. I.C.A. §§ 99F.1, subds. 6-8, 123.92. Horak v. Argosy Gaming Co., 648 N.W.2d 137 (Iowa 2002); West's Key Number Digest, States Key Number Symbol18.57.