This happened back in the late 70's at a DZ in 
 Charlotte Michigan.  A load of us went up in the
 182 for a four way.  Things may have changed
 in the years since, but back then it was popular
 for some jumpers who thought they knew better
 to load the plane in various stages of dress.
 Some would walk on with the jumpsuit and rig in their
 arms.  Others with a jumpsuit on and the rig riding
 their shoulders, and others all geared up ready
 to exit.
  Our ride up was uneventful and the exit went
 as planned.  Our hero was wearing a Stewart
 Sweethog container system with a square main and
 round reserve.  In freefall, we were so focused on
 completing formations that not even the jumper
 himself noticed that he had forgot to put the
 leg straps on ... that is until it was time to open.
  The jumper whipped out his pilot chute and as 
 opening occurred, slid down the harness until the
 junction at the main harness caught in his armpits.
 This was opening shock #1.
  Due to uneven loading on the risers, the jumper had
 a malfunction.  From my perspective some 30 yards
 behind and above, I could tell a cutaway was ahead
 and thought something didn't look right, but things
 happened so fast I didn't realize at the time how 
 wrong things were for the guy (in?) the harness.
 Somehow he managed to cut away the main and
 deploy his reserve without falling out.  Opening shock
 #2.
  He rode the rest of the way down grabbing harness
 with crossed arms, unable to control his direction.  The
 landing was brutal but he was so rattled he didn't even
 care.  He was incoherent most of the rest of the day
 and almost gave up jumping.  Even thinking back
 on that day, as I write this, it makes my pulse race
 and palms sweat.  We crucified ourselves for not
 doing gear checks, but it happened. and maybe others
 can take home a lesson.