An experienced quilter told me that yes some fabrics loose dye when washed and some fabrics are more likely to pick up the color. She has been quilting for over 20 years and gave me the following advice. I have to say with following the rules I haven't had a problem
1. Wash quilt in water temp you usually use
2. Use 1 color catchers if light fabric, more of them with dark fabric. Even 3 or 4 if Batiks
3. The biggest problem is washing a quilt without enough water so if you have a emergency saving type washer or a front loader she suggests going to a laundry mat with really large washers and use that. If its a twin or smaller a standard top washer with the water level at totally full. Her point is that if there is a little water then the bleeding fabric ends up touching the other fabric without water to be a buffer
4. Take it out of the washer immediately
5. Dry however you will continue to dry the quilt.
6. If giving as a gift, send some color catchers with instructions
I believe her and my quilts are proof.
Hope this helps