This video shows federal police at a roadblock. The guy recording it keeps his calm and asks about the nature of the stop and whether he is free to go. The police, for now at least, generally have to inform you that you are being arrested provide a reason. Here, since they did not have any (and apparently they already knew the person driving), they simply let him go. Power for the sake of power.
(Thanks to Ian Bernard for the link)11:49 am on February 8, 2008 Email Manuel Lora