That's a huge given. Best thing they can do is disclaim and say not every safety feature is 100% at all times but collectively everything from seat cushion flotation to the slides are there for your protection. They do not guarantee your survival given every accident is different. etc.

This way they head the ambulance chasers off before they can get started. Every airplane is also it own corporation. That's as far as any lawsuit can go, IMHO.