Not to detract the point being stressed, however, the boards on the roof are 1″ thick, rafters are 2×4 @12″to 16″ O.C., this is more than adequate to bear the individuals weight, should he be tied off? Absolutely, where? Should he be using a longer extension ladder and working around the tree? Sure, but with the hedges being where they are, this may not have provided an adequate area for ladder placement. The only issue that I can see here is that the ladder does not extend 36″ beyond the roof of the shack for safe accessibility. I would say that scaffolding could have been used, we can’t really be certain, also is he removing only the one dead palm frond? if so the scaffolding would be cost prohibitive unless it was owned by the service. I am not negating the situation only being realistic.