One of those bedtime talks with my 7 year old and it goes...
'Mama, I know what bad men looks like. They always wear black and most of them have mouth covers,' MC said.
I asked her where she got those ideas, although I mostly suspected the television's influence. She confirmed it, too as she explained, 'I saw them in TV.'
I had to tell her that she must not always believe the television. That bad men could wear nice clothes, too; that nice men could wear black, too.
What is important is to trust what she feels when she interacts with people. If she dont feel comfortable with the people around her; no matter what color of clothes they have on; then she should avoid them. Or tell us what she feels and we would be there for her.