How is a Hotel responsible for firearm sales?

[Succubus]

Even today, a bar, in many locations in America can be sued and held responsible for selling a drunk too much liquor and they go off and kill someone on the road.

And this hotel was sued for allowing a stockpile of arms to accumulate in a guest's room.

Paddock arrived at Mandalay Bay on September 25, 2017. He was booked into Room 32-135, a complimentary room on the 32nd floor. Four days later, he also checked into the directly-connected Room 32-134. Both suites overlook the site of the concert at Las Vegas Village.

Between September 25 and October 1—the day of the shooting—he stockpiled an arsenal of weapons, associated equipment and ammunition that included fourteen AR-15 rifles (all of which were equipped with bump stocks and twelve of which had 100-round magazines), eight AR-10 rifles, a bolt-action rifle, and a revolver. A bump stock modifies a semi-automatic weapon so that it can shoot in rapid succession, mimicking automatic fire. Often with the help of hotel bellhops, he brought five suitcases to his room on September 25, seven on the 26th, two on the 28th, six on the 30th, and two on October 1.

Twenty two suitcases? I don't know how unusual that is but I would have given it some, 'ello ello ello, wot's all this then? But then I'm a suspicious bastard, just like security guards are expected to be, and are paid to be.