The real issue here is not Wikipedia. It's the fact that for 6 months a single call was enough to shut up the whole global press. Just imagine how often the others call: governments, corporations, Scientology...
That doesn't mean a single call that said "don't run that story about the real reason Sarah Palin resigned" is going to work the same way.
Don't write this or the terrorists strike. Don't write about our soldiers killing and raping in Iraq as they may die in retaliation. Don't write about that epidemic or more people may die due to panic...
News is always about life and death.
This way the Chinese also argue when subduing information about the Tian'anmen massacre "to prevent more people from dying".
You mean "unreasonable" requests like wrt other kidnappings?
Of course it's unreasonable to keep quiet to protect "those people" - they're not reporters.