No boring primers necessary. That element definitely exists in unschooling, but I'm not sure that's a basic tenet. I don't do unstructured homeschooling or relaxed homeschooling. I did do that with Laura, and she will tell you about it with tears. Alex, on the other hand, has never had a lesson from me that he didn't request and initiate.
Labels exist to stop discussion.
Give it a name, put it in a category, and you've captured it and made yourself safe from it. Unschooling scares people, because there are no guarantees. What unschooling is about is freedom. How it appears in different homes is as individual as the child himself. In some cases, unschooling parents will find their child desires a structured curriculum, and they provide it.