A woman is suing a Las Vegas bar over serious injuries she says she suffered on one of its strangest attractions. The machine is built in the shape of male genitals and operates like a mechanical bull. A rider climbs on, the device starts to buck and spin, and the challenge is to stay up without being thrown off. During her turn she was badly hurt, and her lawsuit puts the responsibility for that on the bar. The usual defence in injury claims like this is that a customer accepts the risks the moment she gets on, particularly where waivers are signed first. Whether staff gave proper warnings about the dangers will matter a lot if the case reaches a courtroom. Vegas nightlife runs on attention-grabbing novelties, and the suit tests what happens when one of them leaves a customer in hospital.