I have a 3rd seat in my wagon, which my nine year old daughter used to love to ride in (when the weather was cool.....
) However, I am no longer comfortable with her back there.
It is because the 3rd seat was added by a previous owner, and I don't have the second seat headrests. A kids head could snap back with alarming velocity and force in a collision, and you would be foolish to allow it (like I was).
Please heed this advise!