I originally came across this problem some time back (like years)… it’s very old.

At the time, of course it was debated and I recalled that the answer was the opposite of what one would initially imagine, and also that it was best explained by extrapolating to many more doors.

OK, in my defence when I read the original post I went looking for something to explain and found that page (not being bothered to type much).

Cunningly, I should have read it, because the idea that odds are unchanged in original problem, as argued in the reporter’s article rely on the assumption that MONTY DOESN’T KNOW WHERE THE CAR IS!

However, that clearly isn’t the case (or Monty is incredibly lucky) and hence odds are skewed as a result.

P.S. Dan, that’s as close to an admission you are correct as you’ll get. Of course you cannot take credit for any of it anyhow because this problem is as old as the hills and has been pondered many times on the ‘net!