The straffing parachute post was locked likely because it seems so barbaric.
Fire in The Sky, pg 524:
"The Japanese made it a practice to shoot Allied pilots in their chutes from the start of the war and never ceased the practice".
Lt Sam Logan, USN, Corsair pilot shot down by a Zero 7 June 1943.
He made the mistake of opening his chute at 20k.
A Zero was in the process of making its 3rd firing pass on him. Zero firing both guns, pilot trying to collapse his chute. "I didn't think to pull up my feet.