How is the police able to access camera and microphone? As far as my knowlegde the security of the OS on the phone is quite tight. Maybe apple or Google have built in a backdoor but 5 years ago they were quite resistive towards governments.
We have seen that tech giants are very pliable to the police, I'm not sure why you think otherwise. There are companies whose only purpose is automating requests from police to tech giants and collating it for ease of use.
Also the legislation of EU is quite tight on privacy where cameras are not allowed to be used for tracking individuals. So police is not able to use the information in court.
Even if this is the case it ignores the problem of the police using parallel construction techniques to create a case that is admissible to a court. It also ignores that this is people's privacy being violated and thats wrong even if it never shows up in court.
More reading on traditional uses.