Use your brain and ask before needing. Simple really. And its easy to know which stats are for each class. "This guy might need this, better ask before mindlessly hitting Need!"
This. Furthermore, a lot of people have companions that need the same stats. In the group I usually run with, the companions we all use most ALL want cunning, so me hitting need while others greed is, well, greedy.
As a result we agreed this: if you need you need, if your pet needs you greed, if you don't need you pass.
Anyway, ask your group. No servertranfers or crossrealmshit to clear you of a ninja reputation.