We now know that the regulators and plant operators made wrong assumptions about just how much seismic activity the plants needed to be able to withstand (they were only designed to withstand a 7.9 quake and the one in Japan has now been upgraded to a 9.0).
We also know that Japanese ministers ignored warnings about plant vulnerabilities.
I know what you're thinking. "Do I trust governments and businesses to always do the right thing?" You've got to ask yourself one question:
Do I feel lucky? Well, do ya, punk?