Monty should try and predict whether the player is the type to switch or not. If they are not, and a switch would help them, he should offer the switch. In some of the other cases, perhaps randomly, he should refrain from offering the switch.
If he is behaving purely randomly he should not tell people, or it would be like playing rock paper scissors against a random number generator instead of a human—lower drama.
Monty should try and predict whether the player is the type to switch or not. If they are not, and a switch would help them, he should offer the switch. In some of the other cases, perhaps randomly, he should refrain from offering the switch.
If he is behaving purely randomly he should not tell people, or it would be like playing rock paper scissors against a random number generator instead of a human—lower drama.