I think in this case that the "seen from the back" doesn't mean to not use prints. Heck, I have busy scrap quilts where you can't really see the quilting front or back. I think it would mean something that is detail quilted, like blocks on the front, where the quilting doesn't go through all three layers.
If you like pieced backs, you can always put in a piece of something plain and if you really wanted it to show you could put in a different bobbin thread when working in that area.
Best thing to do is to ask.