Assisted eye witnessing is crowd sourced surveillance. Imagine everyone had the possibility to acquire a magical little camera with compass an gps receiver. Lets say it is in their eyes, so always seeing what the person wearing it sees.

Now let us look at the crowd sourced surveillance aspect. Imagine a criminals face were released as a small file by the police that then could be used in face recognition software. Now every one would have the possibility to run their recordings against the face file.

If you found a face you would simply notify the authorities and handover your recording with the face part.

Now let us look at some of the problems in this system:

1) Protecting the witness (anonymity)

How do we protect the witness from not being revealed to the criminal if not wanting to?

2) Ensuring authenticity of the face file and the sender.

How do we make sure that the police send the face file and that it is indeed the criminals face?

3) Technology

Putting stuff in peoples eye... probably not, but in their sunglasses.. maybe..

Conclusion: Technology is the least problem of the above mentioned three.