Also most of these systems have local control over-rides so it's not like some hacker can make a power plant shut down or blow up. Even something as basic as a sewage lift station would need about three things to fail before you get sewage backing up your drains. I have seen this happen
but usually it just floods the street through the manholes.
A nuclear power plant has a minimum two back-up systems as well as scrambling and containment. Three mile Island demonstrated how well containment actually works.
The fact that someone actually highjacked a plane armed with box cutters is of more concern to me.
