To me Griefing is when a single individual is consistently stalked for the sole purpose of aggravating and inconveniencing the target player.
Under the assumption the target player is not trying to do the same to a tower or its inhabitants outside of pvp designated war times.
Its almost like the character in the tv series " Forever " when he gets killed, his entire body disappears leaving nothing behind. I find that odd though, when he resurrects, its typically nude in the nearest river, and the show has shown his clothes AREN'T left behind, odd dynamic, guess his clothes go where lost socks do?