Just out of curiosity, were any of the red fabrics runners? I mean, did you test them before you washed them as ckcowl suggested? Because if they weren't runners to begin with, then the Dawn didn't really do anything to suspend any dye and it may not actually work for that purpose at all. So next time, if the fabrics ARE runners, you may find yourself in a bit of hot water (pun intended).
As Prism said, the only time I know of that Dawn works the same as Synthrapol is as a surfactant...it makes the fabric more receptive to dye when dyeing...or to remove all coatings from fabric to prepare it for dyeing.