I don't favor coercion, so nobody is going to be forced to say or do anything.
Refusing to answer would be like refusing to help someone who request your help. Considering that answering the question is relatively inexpensive, you really don't have a reason not to do so. Unless you're hiding something, which will make people think of you as selfish.
I wouldn't trust a person that is selective when it comes to answering questions. They'll only say the truth you want to hear, which will contribute to bias and poor understanding of reality.
Moreover, its just plain simpler for a person to systematically tell the truth. Seriously, the mental burden of remembering lies and keeping secrets is probably extremely underrated.
If it helps, I tend to be frank/blunt to an uncomfortable extent. I sort of try not to because people find it off-putting, but I also sometimes don't notice I'm doing it. So it's not like I am in opposition to what you are saying, but I don't necessary see that it would be so great.
(re being able to reply, there's a speed bump built into the site, if you click the time stamp through to the individual comment page you can always reply there)