I've never experience inadvertant ignition with a Bic and frankly don't think that's a realistic concern.

I HAVE had leakage due to breakage - once in the cargo pocket of my pants from a fall, and twice in my pack from rough handling of gear during extremely cold weather (brittle plastic).

I simply moved my lighter deeper into my pack with it had more cushioning. It's a little less convenient to get to but how often do you need immediate access to your lighter? If I was looking for a different way to protect it I'd look for a hard case and put it inside along with some tinder.