Excuse me, P'tach, but while I understand the origin of disappearing Klingon forehead ridges, I am curious as to the similar ridges of Romulans. In all TNG, DS9, VOY, and ENT-era productions they appear with ridges, but in all TOS-era ones, including those made after the ridges were established as canon, they do not appear. Additionally, Spock is able to move about on Romulus without any ridges and apparently attract no attention.