BA let me jump-seat a landing at age 14; it was fantastic. Aged 5 might be a bit young, even if they are one of the pilots children, but presumably the pilot would be able to make a judgement if there own kids can sit still.

To be honest the other thread starts off over the top with statements like "violates international safety regulations". Does it? Which ones? I didn't know there were internationally agreed rules preventing children from entering a cockpit

SkyTeam777 is based in the USA; might explain their view. I suspect this may have been an AF flight, and they are a rule to their own anyway