Not for the first time, but then everybody can make mistakes
I know of one person who can't.
I guess the key factors here would be
Clarity and specificity of the question
Accuracy and completeness of sources
Bias vs Respect for the truth
Declaration of the answer's limitations
and
Delusion vs Hubris
I guess the key factors here would be
Clarity and specificity of the question
Accuracy and completeness of sources
Bias vs Respect for the truth
Declaration of the answer's limitations
and
Delusion vs Hubris