[cperciva]

I would led it slide for maybe a dermatologist.

It's medically relevant far beyond dermatology; having darker skin than normal for one's racial background can be a symptom (e.g., of primary adrenal insufficiency), while knowing a patient's racial background can be important for diagnosing and treating diseases which are far more common in some racial groups than others (e.g., drepanocytosis).

But absolutely agree that it is not relevant to taxi regulation.