No, they aren't very fragile in the first place while off when they are most likely to be moved. It's when they are on that's the risky time. The head is millionths of a inch (micrometers) from the platter. That's just how hdds work so nothing will make it more drop/vibration resistant other than getting the head away from the platter. While parked, hdds are pretty stout, desktop or laptop, and the rest of the pc will be damaged before the hdd is. Being smaller and lighter will help during impact but that's still negligible when the rest of the laptop will be damaged first. If it's a portable/in an enclosure then that may help but that's why they make drop resistant enclosures. It makes no sense to make the hdds more drop resistant when...