I have never been a pre-washer (except for flannels), but I'm making a commissioned quilt with deep purples and greens so ... did for someone else what I haven't been willing to do for myself. I threw a white terry dish cloth in each load just out of curiosity. I did 4 loads - one of greens, one purples, one blacks, and one the purple backing. It's the backing that did the most damage. So ... more trouble? You bet! but ... can't imagine all my hard work and her hard dollars ending up like this if I hadn't pre-washed.
The picture is two dish towels - one that was washed with the purple backing and another for comparison.