MomSparky probably has the best idea, from a fairness perspective.
I hate to think that we're coming down to a world where it's all sue, sue, sue. I will tell you a story. When my daughter started kindergarten, we had just moved to the Bible Belt. I was wondering if I needed to take off my pentacle and scrape the COEXIST sticker off my car in the interest of survival. I went to the school to talk to the principal to find out if bullying the child of the witch would be tolerated.
As soon as I said, "I'm Pagan," the poor woman turned white as the driven snow. Dumb Aspie, I smiled and said, "It's OK; I'm not litigious." The relief in that room was absolutely palpable. She was very good to me and my family after that.
Threatening them with legal action might be the only thing there really is to do. We really might have come to that. But I hope not. Please remember that the reason they're profiling in the first place is that they're afraid-- and, as much as I would like to think it's an altruistic fear, it's mostly fear of getting sued. Stack more fear on top of that-- it might be your best weapon, and it might be all hell breaks loose.
So-- I don't have a whole lot of hope for you. Sadly, I have to say I'd recommend you teach your kid that he must be three times as good, three times as careful, three times as quiet as everyone else. But-- from the hope I don't have-- please-- carrot first. Stick as last resort.
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"Alas, our dried voices when we whisper together are quiet and meaningless, as wind in dry grass, or rats' feet over broken glass in our dry cellar." --TS Eliot, "The Hollow Men"