However....if all of the fabrics in the quilt are deeper, richer colors, you may not notice as much if you get a little bleeding. Mixing those deep greens and purples with any white or very light fabric is where you could have really run into trouble.
On the quilt I'm working on now, I considered doing some accent pieces in white...but almost all of the rest of the quilt is various colors of hand-dyed fabric and batiks. No way will I flirt with disaster by adding whites into the mix.