As a passenger who used to request the privelege of visiting the flight deck in flight I now accept that I have to stay in the passenger cabin. The appearance of flight deck crew to say goodbye gives me the opportunity to thank both the cabin and flight deck crew and (occasionally) ask the flight deck crew a question (no doubt considered banal but always answered with courtesy for which I am grateful). So, if you can stand SLF asking the occasional question then I would encourage you to open the door and step out!