It has been many times said that it doesn't apply to time-travelers, and that the only controversial thing in CT is Marle's disappearance. Well, I have a theory that would explain that as well... It is that the grandfather paradox, doesn't apply to those who have travelled to the End of Time, instead of all those who have time-travelled. I guess this would explain why it applied to Marle at the start of CT's story. What do you ppl think?