Those who think the sound of a shotgun being racked is going to scare someone high on alcohol or drugs [an ever increasing problem] is living in a dream world !!
Many pump and auto shotguns are designed such that the safety just blocks the trigger. If there are worn hammers and sears the gun can easily fire despite the blocked trigger if the gun is bumped ! The old Winchester M97 is a good example . Many old and worn ones are out there and the problem has been known for many years.
And Watson , bring your revolver !