Malfunctions are part of donning a parachute. Anything other than clear air around and you have the potential for other equations to figure in. Hitting with body or canopy can indeed be hazardous at best and fatal at worse. While at Ft Benning going through jump school one student got hung up in the 250 foot free tower. It happens. On mass tactical unit jumps, jumpers can and do get entangled with each other. It happens. All of my jumps were militery static line and only once "had a could have been more serious" malfunction. And only one jump didn't feel right. That was a static line baloon jump at 300ft at the Park in Edinburgh, Scotland, I don't know if that would qualify as a base jump.
Jumping was always exciting enough. I cannot imagine putting on a wing or squirrel suit, and trying to skim down and along mountain sides. And it would certainly be prudent NOT to have the wind blowing into the item being jumped from.
The sky, even more so than the sea, is unforgiving of even the slightest mistake. Airborne!