Father and daughter I can handle. Husband and wife on the flightdeck would be another matter!
Can you imagine the welcome PA;
"Ladies and gentlemen, It's your Captain speaking, welcome aboard flight XXX to Sydney. Assisting me on the flight deck today is my darling wife Sharon. I just want to assure you all that a husband and wife team is quite normal and within our regulations, you have nothing to worry about. We may have had a huge fight last night over some damn sofa she wants to buy but that's ok because the bed in the spare room is quite comfy and I'm feeling well rested. As soon as I can convinced her that I WAS NOT just now flirting with the senior flight attendant, we will be under way. My darling wife will be flying this sector and if she is not too busy nagging me about something else, she will get back to you with some more details once airborne. Thankyou."
