I think you meant they would mistreat Group A more, if they are more heavily weighted, but I do see your point.

I agree that this is a danger. Fortunately, with additional data available, data scientists will be able to show any biases more clearly. If it happens with a rating system, it was happening before the rating system, except now there is the benefit of more data.

Similarly, you could also show if people from Group A (the more weighted group) also rate the police lower, despite similar treatment as those of Group B. The data will cut both ways.

EDIT>> Nvm, you were using "weighted" to mean "the weight of their vote", not "the weight applied to their vote."