I have to agree with this. I use roof jacks a lot, and never use roofing nails to set them, I use 16d sinkers. Roofing nails are often 1" or less, they're rarely into the framing at all even if they were long enough, they're often just into 7/16" OSB, they're often not that straight, and once you start backing them out they get even looser. I do not disagree with the heads snapping off as I have seen it too many times. What I don't get is, why 16d nails? They rarely (never) hit anything but roof decking and then become a hazard in the attic. I have used roof jacks many times and usually with 1.25" hand "driven" (snug) roof nails, 3 per jack, 2-3 bundles of shingles and two dudes working on a 12/12 with never an incident. On the other hand, one of those 4 wheel drive all terrain bucket lifts are a lot more fun than roof jacks[]