Not a lot of hardwoods up here in the Rockies of northern CO where the burger incident happened. I would attribute it to ignorance though not bravery. I have cooked over pine coals many times since but with great care that there are only coals. Some willow or river birch twigs are good for kicking up the fire without risk but they are too small and burn too fast to make an entire camp fire with.
I burn twigs and bark from the cedar/juniper trees on the property over a lump of charcoal made for that purpose as incense when I pray my rosary for my friend who is fighting cancer...