Unbelievable, I had the exact same situation on a visit to South Africa. We were in a Cessna, also with no door, and there were 2 static line jumpers to exit first. They did the exit, and then the rest of us were taken to altitude (even if it is only 9.5k in a Cessna!). Luckily at around 7k the guy sitting in front of me, got up, turned around and started talking to me. He noticed that the guy sitting against the pilot seat had his reserve popping out. The pin had been dislodged whilst leaning against the pilot seat (he was a german jumper and was borrowing dz kit). If he had just stood up when we had got to altitude, he would have definately been pulled right out of the plane. We told him to just keep leaning back, it didn't seem safe for him to move at all, especially not take the rig off as the reserve pilot chute is spring mounted. We all decided to fly the plain down and the dz put us all on the next load. In this situation I don't think it would have been right to climb another 2k and jump with him sitting there, and it probably wouldn't be safe to do that. Granted, if there is an accident, the less jumpers in the plane the better, but if something does go wrong, at least there is the possibility the other jumpers could prevent a big accident. Dunno ? lucky matt