Blonde and ginger women get asked plenty.
I can easily see a shaved head elicit the same dubious approach.
Any woman I've ever talked with has their fair share of weird, inappropriate crap thrown their way, this just par for the course.
I can't really assess whether that question is common, because I am a man and no equivalent of it exists in french, my native language. So I would trust the commenter above that this is a common enough occurrence that their friend has a default response for it