In 1985 one of the key people behind the original IBM PC, along with six others from their group and in many cases their spouses, were killed in a plane crash returning to Texas from a conference in Florida. It's definitely a reasonable policy for critical people.

I had a personal policy, before version control software was so prevalent, of scripting out everything in my databases as part of EOM processes. I can't say that I needed it very often, but it definitely would have been my butt if I hadn't had it.