Personally, we all thrive to uphold our integrity and back stabbing or covering up for one's own mistakes or taking other people's credit for one's own advance are lies most of us wouldn't lower ourselves to.

However, when there is a conflict of interest between business goals and the welfare of the employee, then the line becomes fuzzy. Say your upper management just told you that they will lay off half of your group in six months, but they want you to keep them in the dark because they want the project to be delivered on time without any disruption. And one of your employee senses something wrong and come and ask you whether there will be a layoff coming soon, how would you respond in that situation? I guess my point is sometimes things may not be as black and white as it seems, professionally or personally. We all need to use our judgement in any given situation and make sure our decision will be a good reflection of our own value system.