I've heard a couple of nightmarish stories about labels being removed, replaced, etc., to "change" the creator of the quilt (I can't even imagine such deviousness!). For that reason, I also sign and date (very small) in permanent fabric pen directly onto the backing, right next to the label.
However, because that too can be covered, I also have a very small "signature" that I place on my quilts right on the front - very nearly in the same place on each one wherever I can place it where it will never be noticed unless one is looking for it.
Our creations indeed are works of art and all artists sign their work, some quite obviously. Advantage: It won't be covered on the front.