I have used a hard case on several trips both domestic and overseas. I have never had a problem with damage. Once when I was preparing to board a flight to Ireland, I saw the luggage handler placing my bike onto the conveyor leading into the plane's storage hold. He did not place it on the belt correctly, and I watched in horror as my case fell off the conveyor and crash to the concrete tarmac at least seven or eight feet below. When I got to Ireland and opened the case, not a ding, scratch or dent on the bike...just a couple of little scratches on the case.
When I travel with a hard case, I use a circular tour route which begins and ends at the same airport. The only overnight reservation I make on a tour is where I will be staying the night before I fly out. I make sure they will store my hardcase during my trip before I book a room, then leave the case with them during my tour.