Always, always, always do the right thing. Especially when you think no one is looking. 

It says more about your character than most any other attribute. 
Personally I have a rule to make it super simple for me to remain on track. If he violates my trust with God, my family, or my team I don’t do it. 

I may think it’s right for me but it may not be right for that this simple rule enables to avoid unnecessary moral/emotional conflict.