I was just reading the thread about Jonathan Ellis and saw that one of Henrys guys just fell off a roof and thought it would be a good time to post this.
The biggest excuse I hear about guys not using a harness or tieing off, is that
1. They dont want to drill holes in the roof for an anchor
2. Its hard to find something solid enough to tie off to that will hold them on the ground.
This was thought up by one of AC Lockyers from Mallards Techs about 12 years ago. Ive been using it for about 3 months now and it has already saved me from falling at least once.
You just attach your lanyard to the D ring on your harness, attached the other end to the loop on the top of the anchor, and drop the pole down into a roof vent pipe. These arent made to let you drop 20 feet and catch you as you dangle from the roof mind you. But if you keep the rope tight behind you, and you lose your footing it WILL catch you and keep you from falling.