Ever seen a Silhouette with a furry, fuzzie or frayed edge?  If a Silhouette shade is not hanging level and out of balance then one edge of the fabric will rub against the side of the header or up against the sides of the shade causing damage.  Often customers aren't even aware of what may be causing their shade to fray along the edges if the problem isn't too severe.  It is, however, often easily cured.