you brought it on yourself miss twiddle

I wonder how much of a classical education the painter had? If he had only a cursory one (or didn't pay attention, I guess), maybe he unintentionally decided to take liberties with the toga coloration. Or, perhaps he thought that since quaestors were permitted to wear the broad-border, why wouldn't he wear it? Everyone wants to be the cool kid! Your rationalization makes sense, though, regardless.