DO NOT tie off to a vehicle.....lest someone hop in and drive away, dragging you off the roof.....before you laugh, it has happened...
I would not remove the ridge or drill into someones roof. you are just asking to be blamed for any and all future problems that arise.
Chimney's can be used to tie off but only if you are certain they are stable....so usually not recommended.
Tie off to the back deck has been done by some (just not the handrail) tie off to the support column.
A second man on the roof to hold the rope, the object here is that he probably wont catch you when you fall but stop you from actually falling....
As far as the anchor, I have 3 of them brand new in plastic that I have not figured out how to use since I started doing this.....
"What do you mean we canít get rid of those weeds in time? Then go over there and put some fancy signs with Latin names in front of them."