Is it possible to stop the World Geocoding Service from matching if it fails to find the address?

No. There is no option for preventing the World Geocoding Service from matching if it fails to find the address. The address locator looks for the best match using a minimum match score.

The minimum match score helps users to control how closely addresses have to match their most likely candidate in the reference data to be considered a match. If the best match score is not what the user wants, they can adjust the setting using the minimum match score option in the Geocoding options section of the Address Locator Properties dialog box.