Doesn't ANI work? When I worked at a business with a phone system used for time tracking we relied wholly on ANI as caller id is what is spoofed. However I am not sure if the ANI information is a paid for service or is it being spoofed as well? Caller ID data was always malleable and never to be trusted
ANI does not typically come with end-user lines, and is (sadly) also spoofable. There are already some systems for fraud analytics, but thye have their own issues.
A user can request a "trace" (usually by dialing a feature code), but not only does this hit the user with a ~$20 fee each time, but the information gathered can only be released to law enforcement, and since local law enforcement would need to make the request, it rarely happens.
