Tucks and puckers can happen to the best quilters, so frustrating! It doesn't matter if it is done on a quilting frame or pinned/basted with thread. I was just at the Machine Quilters Exposition (MQX) in Portland, Oregon last week and saw a quilt that had been quilted by a very well known quilter/teacher/author and was astounded to see a small tuck in the backing. I know that the owner of the quilt had to have paid a pretty penny to have this person quilt for them and the quilt/quilting was lovely...but a tuck?? Just goes to show that ANYONE can get a tuck in a quilt backing. If it really bugs you, you can hand sew them down with little needle-turn applique stitches and if the backing is nice and busy, it will be hidden. Or you can applique blocks over the offending areas...or a large label. Appliqueing things to the back of a quilt is also a way to hide stitching when the tension goes off in areas - had to do that with a quilt one time because I didn't want to frog that much quilting...ended up looking totally awesome!