Re: Could Judgment Day have been averted if Sarah hadn't called Ginger
The timeline is a paradox. The T-800 comes back to kill Sarah due to orders from SkyNet. The T-800 is destroyed, and its advanced technology leads to the development of SkyNet.
Also, what was the T-800 going to do if Sarah had an unlisted number?
Dr. Howard, Dr. Fine, Dr. Howard: For duty and humanity! --Men in Black (1934)