The word of a police officer is taken at a higher value in court, in the absence of any other evidence. The police having that power and being entrusted with th

The word of a police officer is taken at a higher value in court, in the absence of any other evidence. The police having that power and being entrusted with the collection of evidence means ordinary citizens are already at a great disadvantage once in court. Surveillance is sometimes the only resort the public have to defend themselves from abuse. Not saying that the police are abusive by definition, but when they do act in that manner (or tamper with evidence), there is little an ordinary citizen can do to defend himself. Surveillance has the great advantage that it doesn't particularly hinder honest officers in the line of duty, it only trips up the abusers.