The Security Mentor

Whisteblowers, skip tracers, and private investigators have legitimate reasons to make the wrong caller ID information appear when they call someone. There are about five companies that offer a service to let them do that.

Funnily enough, not all the people who use a service that changes their caller ID information are honest. Some of them have been stealing from stupid companies that rely on caller ID to authenticate customers.

Which has led to government investigations. Some of these have been fishing expeditions, demanding detailed information about every user of the service, regardless of whether they were suspecting of wrongdoing.

Caller ID spoofing firms have given government investigators complete customer lists and records. If you called the New York Times anonymously under fake caller ID to report that your company is paying kickbacks on a government contract, guess what? You're toast.