"It also gives them an advantage in situations such as these - anyone that we speak with could be a vampire or have done this." Although she'd like to believe enough in her judgement that Martha hadn't done this.

"I've only ever yet found one way to detect vampires." Although it registered her as a vampire, also. "Although whether it would work on each vampire here? It's hard to say." And it wasn't something that she wished to meddle with, either.