Police do those things because the camera is effective. The solution here is to punish officers for disabling or obscuring their cameras, not to get rid of the cameras.

It's the DRM argument - publishers don't stop using Denuvo because someone always manages to crack it, they use it to stop little Timmy from copying Assassins Creed 27 on to a USB drive for his friend Dave. In the same way, Officer Porkchop can't openly conspire with Lieutenant Bacon to plant evidence, because the audio is on record. But doubtlessly, the Porcine Patrollers will manage when it really counts, maybe just not as often.

well the first level, any evidence collected and released is more than zero, which is the baseline before cameras. They are frequently included in trials. They are also sometimes released to the public in high profile cases, usually in the interest of exonerating the police, but which is also sometimes informative.

Do you have any reason you do you think that they are a net negative?