Well, when she said that the arists and authors aren't supposed to have contact, and do not have contact in most cases, she was specifically talking about illustrations within the book, not the cover art. ::shrug:: (She has no professional experience herself, yet, but her program works a lot with people in the industry; make of that what you will.)

The cover of a text-only novel is pretty much stands apart from the book; reprints will often feature entirely new art, anyway. The art within the pages of a picture book is a much bigger deal, since it's an immediate visual interpretation of the text, and literally half the point. That's what I find so bizarre--a collaborative work where collaboration means throwing two people at a work and forbidding them to interact.