[1] In Canada, the caller name information can be applied either by the client's own equipment (PBX), or by the originating carrier.
The altering of caller ID information is allowed, provided it does not violate regulations in place regarding spoofing or fraud.
Rather, the terminating carrier is responsible for providing the Caller ID information to its customer.
[3] Incorrect Caller ID information can be displayed under a variety of circumstances.
Incumbent Local Exchange Carriers (ILEC) usually provide the most correct information.