Tesa Constantine

I was told that if I have my RLV activated, that I can be captured to the point that my avatar can no longer be used unless the captor releases me. Is this totally true? Even if I have an owner assigned to my collar, can't they be able to get me out of the situation?

I was told that once I derender someone they won't show up again while in the region I derendered but that doesn't seem to be the case. I have blocked this person and they show as a cloud. I derender but not 2 secs later,their cloud shows up again. How can I permanently derender them?