Other stuff like lie detectors which are in quite often use in the US are complete nonsense.
Witnesses are inherently unreliable, rarely they produce even remotely accurate testimonies, and in most cases tell the cops what they want to hear rather than what has actually happened.
Expert witnesses including law enforcement agents constantly give flawed testimonies and are inherently biased based on the nature of the case and the apparent guilt of the perpetrator. Paid expert witnesses are even worse because they have a clear incentive to give testimony that will strengthen the case for the party which paid for their services, both state and federal level prosecutors have their pet experts that will tell the jury just what they want them to hear, same goes for many large criminal law firms.
So far only 2 types of evidence seem to increase conviction rates while drastically decrease wrongful convictions and these are audio/video recordings and DNA.
While I understand the fact that people do not like to be watched, and a smarter man that me once said that those who are willing to give up liberty for security are not worthy of either. In our current reality however increased privacy might actually result in loss of liberty, especially if you are a member of an at-risk group as far as unlawful convictions go.
If the police use a search light for better visibility a night? Not spying. Use binoculars? Not spying. Fly overhead? Not spying. Look into the windows of a barn which is "accessible only after crossing a series of "ranch-style" fences and situated one-half mile from the public road"? Not spying.
At least, not according to the US Supreme Court. There are of course many who object.
If we can't even indict police who shoot people in the back to go to trial(1), how can anyone believe cops won't use this to stalk ex girlfriends or anyone else they feel randomly curious about?