When I think about what causes a fabric to ravel, I see seams that are unprotected and loose. A quilt has all the seams pressed flat, are inside the sandwich, and can be crossed over by quilting several times, thus giving the entire quilt more strength. So even tho washed many times, the seams should not ravel as there is no way for the fabric to move. Smaller seams than 1/4" will increase the risk, but like the other posters have said, we've all had to use the smaller seams to make that piece fit, taking extra care to secure that section. I am not afraid of my seams raveling at all.