Grief

Griefing is the destruction or modification of one's build without permission from the owner. This is one of the most known rules that lots of players who don't read the rules happen to break it and get banned. So, even breaking someone else's block or adding one block to someone's build counts as Grief in our terms.

There is no size requirements for griefing: even removing a single cobblestone placed by a player in the wild counts as griefing.