Roadblock and speed trap warnings using tech

[Vlad]

imagine someone developed an (iphone) app like trapster, but where ppl could report crime incidents. would the police be against that too b/c it might make them look incompetent? I can imagine some areas would turn deep red (assuming red is the colour of a crime spot)

 

[Albereth]

it is illegal p.
Defeating the ends of justice

What ends of justice have been defeated? If the person is speeding he will get caught and issued with a fine. If he slows down, he is not speeding and cannot get a fine and there is no need for 'justice'.