Instead of burning them, though, they should drain the oil, and put Karo in the fuel tanks, a la Ed Abbey.
Any guy whose dick is so small he needs a hummer should get a penis implant. Would be cheaper, too!
Why? GriGris are fine for sport routes. If you are anchored to the ground, though, a grigri can increase forces on your gear as there is no slippage in the system. Don't worry about it for sport climbing.
To feed rope fast with a grigri, the only possible method is to hold the cam down with one hand and pull rope though the device with the other. Just make sure to let go of the cam if the climber falls!
I've been hurt on overhanging terrain when my belayer didn't leave enough slack in the system. I peeled from a roof, and smacked into the wall below it. Sprained ankle, , sucked. Unless you're climbing some very runout low-angled slabs, don't worry about reeling in rope.