I have flown with several companies that still allow cockpit visits and/or fly with an open door. In all cases I would judge these companies to be low-risk as potential candidates for terrorist actions. Different circumstances should dictate different measures and be left at the Captain's discretion. As pax on let us say an American Airlines B777, I would appreciate the locked door. On the other hand, if I'm on a short inter-island flight on a carrier whose country is not high on the terrorists target list, I have no qualms about an open door. Yes, I know, there are always exceptions (nutters etc) but the odds are that I've more chance of winning the lottery! I say "thank goodness" that flying can still be fun with some airlines.