Any policeman with a gun strapped to his side is an inititial, immediate threat. The fact that it's impossible to trust them, even to do what is in their best interests, makes any situation where you are near one more volatile. The fact that police unions across the country still cater to Harry Anslingers beliefs, a man who died 60 years ago, over any conceivable application of American liberties or ideals, shows that not a single man with a badge can be trusted. Any encounter with the police must be realized to perhaps be the last thing you will experience as a living human being on this planet. There is no compromise, they can, and will terminate you as a sentient being for any reason at their own whim, and even though you will be dead, they will face no accountability by their peers.