You are asking a question about culture, not philosophy.
A given reprimand or intervention may have a good or a bad outcome. You have to ask, how will you feel if it is a bad outcome? In a previous era, children were given corporal punishment, and if they turned out criminal a punisher would say, at least I tried! Now in modern times, we would say, no wonder they turned out bad, it was the corporal punishment!
Different people respond to boundary enforcement differently. We all need boundaries though. Look to the geist of your organisation.
No one should be afraid of mirrors, apart from the dangers of over-absorption. It is among the oldest tenets to do as we would be done by. We learn through the action of mirror neurons, and are affected by the actions of others in a deep way. One of the deepest metaphors for teaching in Buddhism is holding up a mirror so the student lwarns from themselves. Always be showing the mirror.
Being really present in the moment is very helpful. Often more can be done pointing put an error clearly as ot is made, than through say a formal meeting about a list of failings. Believe in the good spirit of others wherever you can, choose to believe they have good intentions unless they themselves disprove that.