1. Police have extraordinary power over others.
2. Juries believe them by default.
This gives them much higher requirements for accountability than most people.
I do really like the idea though. Human memories are incredibly inaccurate, but we believe our own memories and can't really do otherwise. If we had the option of a surrogate memory that could be really transformational. Imagine what that would do to your perception of time and your discount rate if you could have perfect recall of your whole life?