Not quite good enough! You have to make it clear that the host will always "open another door" no matter what, and that the contestant knows that fact. Otherw

Not quite good enough! You have to make it clear that the host will always "open another door" no matter what, and that the contestant knows that fact. Otherwise, the contestant might reasonably think that he might only be offered the chance to change when the host knows that a change will be the wrong move. You could say that the wording given kind of implies the always, but it's not completely clear. So, the claim that it's almost always worded poorly is reasonable.