Silence and Ethics
There are times when you have an ethical obligation to speak up. I'm not just talking about whistle-blower situations. Although whistle-blowers exhibit courage, the silence they break is one that cries out for action.
More common is the person who maintains silence as a form of deception and who leads others to reasonably assume that he or she agrees with their position. The silent deceiver may later argue that no position was taken but that is a mere technicality. Their silence denoted assent and a reasonable interpretation of their behavior is that they agreed with what was said or decided upon.
Even if the person is still pondering a position, that interim status should be declared. If it is likely that agreement was assumed, there is an ethical obligation to clarify the matter before too many days have passed.
"I did not lie, I just did not tell the truth" deserves no pass.