I've been caught before, so I always make a point of pre-washing any red fabric that comes through my door. In fact with this quilt, I re-washed the yardage just to be sure. I don't wash pre-cuts - I've had bad experience with them shrinking and distorting as a result of being pre-washed. This quilt top that I showed a few days ago, which had a lovely white with red polka dot border around the heart now has a not so lovely splotchy pink with red polka dot border. :( There was one red charm square used in making that heart that caused the grief, even though I had thrown in two colour catchers with this little quilt to try and ensure that any stray colour would not be transferred to the white of the quilt.
and I'd even put a lovely bias cut gingham binding on it
Live and learn - there will be no more pre-cut reds of any type going in a quilt that contains white without prewashing or colour fast checking them.