"He who marches out of step hears another drum." ~ Ken Kesey
Yes, an underbase and for consistency and ease of production so you don't fart around with not printing this and do print that..., I'd leave it (as is) on every color. Meaning, print white ink on white...red ink on red..blue ink on blue shirts (as an example). Run that baby. You gotta print white ink anyways for the star, you use an underbase.
Well doggone I'm wrong on this one Darryl