I don't think that it matters. It is entirely a personal choice. If you are doing all of the binding by machine, wrapping it from the back to the front and top stitching it down, ensures that your binding looks great on the front. This way you can even select a decorative stitch and have it straight and even. If you are planning on hand stitching it down, everyone I know, stitches it to the front and wraps it to the back. Your binding, your choice. As my daughter reminds me "The baby won't care!"