There will always be a conflict in your classroom about how something is not fair and this poster would be great to have up in the classroom. When students start a confrotnation on conflict point at the poster and have each student read it aloud.
Lots of people today need to really THINK before they speak. Too many people have forgotten how to be kind and speak with respect. The saddest part for me is that children are watching and learning how to imitate the same behavior.