I, too, cannot just go totally random scrappy, but I sure love the quilts of those quilts that are done that way. I can be fairly loose with my crumb block quilts...you can see my quilts
here. At least I hope the link works. The meaning of scrap quilts has evolved for me over time. My mom made true scrap quilts...she was lucky to buy enough yardage to make sashing and have for a backing. Her tops were made of scraps of fabric left over from dresses she made us girls and herself. And scraps from a sewing factory every now and then.
Now I consider a scrap quilt anything that is not planned...with a variety of fabrics. It doesn't matter to me if the fabrics come from leftover projects or from fabric collected over a period of time just to have.