It's personal preference.
Once I learned that Harriet Hargrave doesn't pre-wash, I stopped pre-washing. I would consider pre-washing if I were going to make an heirloom quality quilt, but the fact is that my quilts are all meant for heavy family use. Harriet Hargrave tests each fabric for colorfastness before incorporating it into a quilt. Basically it is a matter of soaking a small square of fabric in a glass of water, checking the water color, and rubbing the wet fabric on white fabric to make sure no color rubs off.
I test only fabrics I suspect might be terrible bleeders. Usually these are solid or almost-solid reds that don't look or feel quite right, or solid blacks. I haven't found any particular bleeding problem with batiks or prints.
The precaution I take is to always wash the quilt with Synthrapol after it is finished. Synthrapol will suspend any unset dye particles in the water so they get rinsed away and don't have a chance to settle on other fabrics. If I see the wash water color, I do a few subsequent washes with Synthrapol too just to make sure that all of the unset dye is gone.
So far no problem with this approach, and it leaves me more time to actually quilt. Otherwise most of my available time would be spent washing, drying and folding fabric.
I like the heirloom look for my quilts (soft and slightly puffed) so shrinkage of fabric is not an issue for me.