I'm sure Lance gave him fair warning, kind of like he gave us a warning in his blog. I'm thinking he probably told Justin that obviously, it was a part of the book, but it was written in the perspective of how he felt at the time of the split. Or at least I hope he had the common sense to do that!
I don't know. So far I find it hard to believe he showed any of this to Justin.

Or maybe Justin really is a great guy, admitted he could have handled things better and told Lance to go ahead and do what he had to do.

Nah, that couldn't be true. Justin is too much of an "asshole".