I'd rather be inconvenienced by a few erroneous predictions than have no predictions at all and no effort made by governments to keep people safe from those disasters because some people might get annoyed if they're wrong.
there are other options than those two, and you blithely ignore the cost of this Tsunami warning. In Japan alone it shut down a huge chunk of the national economy for two days....plus the cost of evacuation of nearly 600,000 households. We are talking of costs that run into the billions I'll bet, and while the cost of the tsunami damage was minimal to non-existant.
this happened in America with hurricane Rita (after katrina) as well, the authorities went ape **** over a little storm, and so the cost of the warning execution far outpaced storm damage
there are many costs to exaggerated warnings, some in lives in future events, some in dollars upfront.
I think that citizens have the right to know the truth about the expertise of those sounding the alarm, so as to be able to make sound personal decisions. Furthermore, governments are obligated to be honest.