I have never pre-washed a single piece of fabric and have never had a bleeder. And I've made over 50 quilts. I steam iron my quilt fabric before I sew and wash the quilt after it's all done and everything has been perfect! I just don't want to waste all that time washing and all that extra time ironing it so much longer after it's been washed. I know how wrinkled a washed pieced of fabric can look like. It's not for me.
But I do have a bunch of Kona Solids and I think I will pre-wash those. When I look at those, they call out 'Bleeders' to me!