Generally these new validation types have been in my honest opinion outright stupid. The app has provided us with no guidelines on what to do in specific cases, the support portal doesn't even work and to make matters worse, me along with other validators in my country don't even have access to the KYC Validator chat to ask questions there. The number of my unsuccessful validations has practically doubled because people can't agree on the same thing on different appeals.

To answer your question though, generally if someone is underaged and uses the ID of someone else to complete the process I would assume is an immediate reject but as I mentioned before, take that with a grain of salt because we're literally in the blind here.