Yesterday, I was looking at gig bags for the concertina. My hard case is a good one, but boxy and I was hoping to find an easier-to-carry alternative. Instead, I found an old post from John Dipper in which he listed various concertinas that came to him in need of repair because they were dropped whilst in gig bags. That night, walking to a session, I slipped on the ice and fell hard---right onto my hard case. The case sustained a bit of damage in that the vinyl was scratched off the wood. My shoulders, elbow, and wrist were a bit strained. My Morse Ceili? Totally fine.
So until they invent an air-bag gig bag, I'll be keeping my concertina in its hard case.
Christine