In Barry v. Stop & Shop, Inc., 335 Mass. 767, 140 N.E.2d 198 (Mass. 1957), David Barry, a water department employee, was, at the request of Stop and Shop, investigating flooding in the cellar of the store when an overhead trap door fell and hit Barry on the head. Generally, a landowner must warn a water department employee of known dangers of this sort. Yet, the Barry court found there was no liability on the part of Stop & Shop because "everything connected with the situation was open and obvious. A warning by the defendant would not give the plaintiff more than he could learn at a glance." 140 N.E.2d at 199.