1800ed
FO was PIC? Interesting, that would imply that he was a both steat trained TRI or TRE assessing a line captain - can you please confirm? And if this was an assessment or training flight then the probability of a flight deck visitor is pretty slim, wouldn't you agree? Then again, if you know some more could you please shed some light?
As for the flight deck visitors, when I was a wannabe nipper I regularly used to get flight deck visits - taught me quite a bit about what would be involved in my eventual career. Anyway, as of next year I will be flying an aircraft where they can see (and walk into) the flight deck at any stage (although poking their head in would be a bit on the naughty side!).
RIX