Or maybe they recognized before Dart wented to sleep in wrapestuff, but he was so sad after Shu-Shen was killed that he didn't want to join at first with Serrin? And maybe Serrin was scared to for a while?
Serrin was what, a few months old when Dart went into wrapsuff? One shouldn't trust Blair and his logic, but still, I don't think even he would do that. :o