FTA: "WhatsApp server has no knowledge of whether users have enabled the change notifications, or whether users have verified safety numbers." If it's off by

FTA: "WhatsApp server has no knowledge of whether users have enabled the change notifications, or whether users have verified safety numbers." If it's off by default, then the answer is likely to be near zero, as it often is with default options. This isn't an argument about the security of the app (which I have no background to know), more of a comment on relying on non-default behavior.