Why not? Auto pilot? Electric rudder trim switch located somewhere else? Other? Perhaps they are there if the electric system fails or ?
I don't fly the A340, so can't speak to that, but in the airplane I fly, the rudder pedals don't get used much in flight other than an engine-out situation. There is no autopilot input to the rudder pedals, however, and the only time the rudders (there are two) provide a turn coordination function is when the flaps are extended. The rudder is large, and the aircraft has a function which progressively limits the rudder deflection as the airspeed increases. Too much rudder input at the wrong time can cause aircraft damage.
A few of our aircraft do have rudder input when the third autopilot is used during an autoland, but not very many do; in most of ours, pilot rudder input is still required to maintain the centerline during the landing roll. We seldom do autolands, however; most of us do hand-flown approaches each time or every other time, and almost all our landings are hand-flown.
As for getting to see the cockpit, usually it's a matter of asking. Most crew are quite willing to show off the airplane, and in most cases you'd be more than welcome to get your picture taken in the left or right seat. I've done it for many people.
Last month I caught a commercial flight back from Dubai on Emirates on an A380. I hadn't been in one before, and got a tour of the flight deck after everyone was off the airplane. Fancy stuff. (Didn't care for the airplane; not enough lavatories).
A month or so ago in southern Afghanistan, I got a tour of an IL-76 from some very friendly Russian gentlemen. Not a lot of English on their part, but they were very gracious in taking the time to show off their aircraft.
A month and a half ago, I went to an open house and happened on a PB4Y-2, which is a Navy version of the B-24. There are only four left flying; this was one of them, and as it turned out, was the last heavy tanker that I flew. I spent about a half hour in the cockpit; it looked as familiar today as it did when I made my last flight in the airplane.
We work alongside AN-124's and Harriers and Hercs and Ospreys, and all kinds of stuff in between, but getting a chance to jump in the other guy's aircraft doesn't crop up very often. If you happen to be a paying customer on your way from A to B sometime, however, ask the flight attendant or one of the pilots if you can sit in the cockpit. I'm willing to bet that the Captain will hold the camera if you'd like your picture in one of the seats.
