I took a freind up today and he asked how something like that can happen. My
answer was simple, their human.

Its SO easy!!!!!!!

It is... and my understanding is that's the reason for the sterile
cockpit rule. Incidentally, there was an off-duty pilot sitting in the
jumpseat in the cockpit along for the ride on the Comair flight.
Wouldn't surprise me if things got a little too relaxed that early in
the morning for just a brief moment.

--
Guy