If the host can choose between doing nothing and revealing a goat, and the host wants the contestant to lose, then the contestant's best strategy is to never sw

If the host can choose between doing nothing and revealing a goat, and the host wants the contestant to lose, then the contestant's best strategy is to never switch, in order to avoid being exploited by a host who only reveals a goat when switching would lose. Any reader who wrote in to say the probabilities were 50-50 after a goat was revealed was probably not thinking the host wanted the contestant to lose (or to win).