Claire should mark good Lottie in some way so if she meets bad Lottie she’ll be able to tell. Or if it comes to a showdown between the two Lotties and Claire, and Claire has some kind of Doom-Ray she’ll know which one to point it at. You can’t be too careful. Or she could tell good Lottie a secret and then when the confrontation occurs she could ask “What was the name of my pet terrapin when I was a child”