From what I've seen it's not the frantic screaming of a baby that doesn't know that it's mother exists when he cannot see her, it's the frustrated cries of an over tired child that doesn't want to go to bed and is dealing with a big change in what's expected from bedtime. I would agree that infants wouldn't benefit from CIO but I'm fine with the techniques I've seen for bedtime.
Shutting down communication (verbally and physically--aside from hualing the child to bed) seems like the antithesis of meeting emotional needs. When a child is calling out, "Mamamamammamamamamma...." and sobbing and the mother won't look at the kid? How is that in line with AP?