I was recently written up for a violation. Previously another employee did the same thing and was not written up. Is this fair?

I am not licensed to practice law in Virginia so the following should not be taken as legal advice but simply as information intended to be helpful. If you need legal advice, please consult a lawyer who holds Virginia licensure.

You ask, "Is this fair?" The answer is, from a legal standpoint, it doesn't matter whether it's fair; what matters is whether it's illegal. Employers do all kinds of unfair things and the law allows them to do so. Discrimination on the basis of "who do we like better" or "who do we trust more" is perfectly legal and occurs all the time. It's only when discrimination on the basis of race, religion, gender, color, national origin, and the like occurs that it becomes unlawful. Based on the facts you recite, I do not hear any claim of unlawful discrimination.