Neither were they military parachutists.....
These were sport jumpers?!! And they planned a jump with a freefall that never reached terminal velocity? And that was done at such low altitude that opening just a very few seconds late would result in their death? Not even smoke jumpers do that, and they arguably take the greatest risks of any jumpers. Before I was confused and your previous reply cleared that up. My confusion was caused by a difference of procedure. But now I'm incredulous. I've never encountered sport jumpers that planned such jumps. Never. I must live a very sheltered life.