For those who have (for some unfathomable reason) not yet watched the HBO series or the 1973 original, Westworld is a robotic amusement park, populated by incredibly lifelike machines (hosts) where park visitors (guests) can go and indulge their thirst for adventure, or alternatively satisfy their darkest desires.
Imagine for a second that such a place actually existed. At any given point, there would be many human guests and thousands of hosts in the park. In this Westworld-like place, human guests would be murdering robotic hosts on a regular basis, as would some of the hosts. The hosts are simply repaired, memory wiped, and placed back in the park. So far so good.
The machines are prevented from killing or maiming the guests by programming directives, which I'm willing to accept, since machines could have built-in ways to identify each other. But given that guests and hosts are outwardly at least physically indistinguishable, how on earth can I get my guests to know not to kill each other? It can be argued that bullets in such an amusement park are made such that they cannot hurt humans, but there are explosives, knives, ropes, water, rocks, sharp sticks, tall buildings etc.
How can a no-holds-barred amusement park prevent its human visitors from killing each other?