Sure, you can argue that despite being allowed to, most police departments do not discriminate in that way, but the legal precedent provides credence and legitimacy to the stereotype, regardless of its truthfulness, which is what I pointed out. I don't think any real data on this would be available, though, so I think most people (you and I included) just go by vibe, so in the absence of evidence one way or the other, the stereotypes will prevail, regardless of accuracy.