Of course it's contrived. There was once a real occasion when the first three letters were CUN and the contestant asked for a consonant, but recording was stopped at that point, the letters were put back in the pile in a different order and they went for a retake. Let's face it, if that particular combination of letters really did come up (which it wouldn't, because the director wouldn't let it go that far), there wouldn't be a small amount of suppressed giggling, there'd be torrents of laughter. And anyway, the rules say the contestant has to pick at least three vowels, and there's only two in that selection.