If you triple-filtered every conversation you had, it would be a totally new experience. Most people don't think before they start talking about someone and if you were there to ask them those three questions, they probably wouldn't understand why you were. I think that triple-filtering everything is a good idea; it would most likely help with all the gossip that goes around all the time.
I think people gossip, even though they know how it feels, because everybody does it no matter who gets hurt or anything. Sure, we know it's wrong and it does hurt people, but then we think, "Well, I got hurt because of gossip, so it's alright if I gossip, too." This is hardly the case. It is wrong to gossip about people, whether you are being talked about or not; we shouldn't go around doing it.