I hate to be the one to rain on the parade, but using knives near a loaded climbing rope is begging for trouble. The slightest nick on the rope and it parts. I had to see it to believe it. One of my climbing/caving buddies had a rope with a weak spot that necked down when it was under load. After the trip where I noticed the problem, we inspected the rope, inch by inch. It looked great. So we set up a pulley off a ceiling joist in his garage and I ascended the rope while he lowered me at the same rate. Sure enough, about 30 feet from the far(of course) end, the hourglass appeared. Being cheap, and figuring that there were a lot of dandy uses for a 120 foot rope, we decided to trim it. We'd heard that using a knife near a loaded rope was dangerous, so we decided to see just how easy it would be to cut. Steve whipped out his trusty SAK while I stood in slings about 3 inches above the garage floor. The instant the edge touched that rope, it was just gone and I was standing on the floor. We were both pretty freaked out.
Hopefully, someone will set up a demo for all these guys so that no one gets the bright idea of using his shiny new knife while he's hanging off a rope.