Most folks don't know the seriousness of the matter and have no idea what they're doing. The radio station created an event that was an attractive nusiance and had the legal duty to find out and know and then to inform the contestants of all the hazards and then to protect them from the serious injury and harm their event was likely to cause. See #60.
2 very liberal concepts.
Care to guess when the nuisance doctrine was embellished in the US and who appointed the judges which turned long standing common law on its head?