I'm not sure that you can just multiply those probabilities (are they both uncorrelated? Can autistic people even become psychopathic?), but, 0.027% * 300 milli

I'm not sure that you can just multiply those probabilities (are they both uncorrelated? Can autistic people even become psychopathic?), but, 0.027% * 300 million people in the US = 81,000 hypothetical autistic psychopaths, which is over 1600 per state. That's plenty to worry about from an administrative (e.g. police) standpoint.