: Why would Pippin's innocence make his statements suspect? Rather, he shows perception in realizing (in hindsight) that Treebeard knew or suspected that Gandalf was alive.

The point is that we are trying to use Pippin as a good witness to what was happening. Unfortunately, Pippin's naivette is only matched by his curiosity, which in that combination was very dangerous. It's Pippin that drops the stone down the well in Moria, Pippin who steals and looks into the palantir. I am not saying that his perception was incorrect, I am only saying that his statements are suspect from his overly naive and overly curious nature.

-RR