Though I used to fully accept such ideas I'm not at all sure at present where I stand w/ the whole shape shifting reptillian thing personally.
*that said*
I knew a young female plastic surgeon who understandably took close notice of human faces as that was the primary area of her profession. She was definitely not of the 'woo woo' 'ufo' crowd though her husband was. He and I were talking about this topic and out of the blue she recounted how she was once on a commercial airline trip casually looking down the row of heads in front of her when she noticed one man with some particularly interesting ears but not out of the realm of 'human'. As she pondered them they shifted for a brief moment into what she described as 'reptillian'. As she was trying to grasp what she just saw the man turned around and glared straight at her w/ such menace it quite frightened her.
Just laying that out for consideration.