I've seen a photo which recreates the condition that Sean's seat handle and pin were believed to be in when he climbed into the cockpit on that fateful day. Based on what I've seen, I woul believe it if you told me that 100 people had missed the unsafe condition. Viewed from the front of the seat, the condition is obvious, but cockpit access checks are always carried out from above, from where the condition is not obvious at all. There are subtle visual clues and I'm told these have now been widely promulgated to the user community. VSO conspiracy theories are probably wide of the mark on this occasion.