My kids aren't Asian and have them. They are very common in mixed babies, my husband is Latin. My boys have them on their lower back. My oldest is dark so the spot is darker like a bruise. My daughter is light like me, she was born with a Stork Bite on her forehead (red spot). Those fade away. It does appear when she gets mad and cries....lol

They have never fooled me because I know about them but I can completely understand how someone can be fooled by them. They can be quite large in some cases.