As the rather stuffy writer of the Bestiary states, "Pirates have their own crude tradition of flags and symbols." This is true in the real world as well, though I actually think that pirate flags are a rather fascinating topic. And given just how blood-drenched some real-world lords and knights were, I'd accord their heraldry the same amount of respect as I would a pirate flag. That is no actual respect at all, just a healthy dose of terror.