Its the same with everything 🙂

The risk and probability of smoke in the cockpit happening / possible cost of a crash will be less (in terms of monetary reimbursement) Than the cost of refitting all aircraft with the system 🙂

I know its an unrelated topic, my grandfather runs the lloyds of london syndicate that insures nuclear power stations, including the japanese ones.

All of these powerstations could be built with every concieveable redundancy in place, prepared for every single type of completely unlikely situation.

The cost of adding these parts is weighed up against the probability/risk of it happening

Where do you draw the line 🙂