I don't even understand the point of shifting the civil liability from the police dept to a low wage employee who will not be able to afford the compensation.
My understanding is that the people at the police department thought what they did was illegal and they should be arrested for that. Turns out they were wrong. I get that the system may make it too easy for people in bad faith to get away with things. And the reason why comparing it to development is that the developer and the user's goals are usually aligned, whereas there are different incentives in place for police work, so it's harder to rely on good faith.
I'm not saying that QI doesn't need to be reviewed, just that the notion that police officers should never take into custody someone who's innocent is not realistic. It just can't work together with democracy and the rule of law. The only possibility of police officers only arresting guilty people is if they are themselves the judges.
If this sounds absurd, it is: https://eji.org/issues/qualified-immunity/