The pilot should be there when the Software fails, and that's why he shouldn't be busy with something else. It adds to security, and it's worth it (from my point of view) whatever is the cost.
You can't say "whatever the cost". What if it were $1 trillion per passenger? Obviously it's not, but there's some point at which you would change your mind. You have to assign a cost to these decisions in order to have a well reasoned discussion. The EPA, CPSC, NRC, OSHA, and OMB for example all use varying costs of life to make decisions with the value of one human life ranging from $1-$8 million.
