I've done pannier and backpack. Used to wrap it in my change of clothes, then put the entire thing in a layer of grocery bags or two, based on wetness. When on my back I've crashed in the winter, didn't sustain any real damage. When having it in the pannier, I put it on the side opposite of the side I laydown on, when I have time to process that in OH S*** kind of moments. That way it won't scrape along side the road in a minor emergency, in a real emergency, who cares, work will buy me a new one, or I'm dead anyways.