Banjo Johnny nailed the flaw in the quoted advice. IF the hard case in question were pure steel, it might transfer the impact energy to its contents. But seeing as hard cases are made of plastic and LINED WITH CUSHIONING MATERIAL, they absorb the great majority of any blow. In other words, they act like a modern crash helmet, as Davecoje alluded, not like a plain steel pot as some misguided brochure writer seems to believe.