danger

CONT: The hallmark of an invitor's duty ... is that his responsibility extends not only to dangers which he knows, but also to those which he ought to know. In short, he is under an obligation to take affirmative steps to ascertain the existence of, and eliminate, perils that a reasonable inspection would disclose.
CONT: ... it is only when (the occupier) has failed to warn of special dangers actually known to him, or is responsible for quite unusual hazards ... that he may be liable as an invitor.