User Blocked

So I had this dream that when you blocked someone on Facebook, you do not only block them online, but also in real life. I had someone blocked and they couldn't see me and I couldn't see them. We were invisible to eachother. So I was having a conversation with one of our mutual friends, and we were sitting in a group. I was talking to them about the problems I was having with this person. And the actual person was sitting right there and I didn't even know it. I realized it later when I was speaking to my sister and she pointed it out to me. But they couldn't hear me only what the other person was saying in reaction to what I said. But I was safe. I don't think he heard me and just assumed she was talking to someone.