it’s not clear that he’s following Monty Hall rules
Whenever I see a badly-specified Monty Hall Problem, I always imagine the host saying something like “Oh, you want to pick door number 1? Well, guess what - the car was behind door number 3 all along! You get nothing but a goat!” And only when you initially pick a door with the car does the host ask “Are you sure you wouldn’t rather switch to door number 2? Look, there is even a goat behind door number 3!” Switching doors 100% gurantees you get a goat… or 50% silver balls in this case.
Whenever I see a badly-specified Monty Hall Problem, I always imagine the host saying something like “Oh, you want to pick door number 1? Well, guess what - the car was behind door number 3 all along! You get nothing but a goat!” And only when you initially pick a door with the car does the host ask “Are you sure you wouldn’t rather switch to door number 2? Look, there is even a goat behind door number 3!” Switching doors 100% gurantees you get a goat… or 50% silver balls in this case.