Well, that all helps explain why Wendy doesn't transform - it isn't certain whether she inherited lycanthropy from her mom, and the onset of full lycanthropy in a latent victim is unpredictable.
As for the DCM hairclip, I guess that's a precautionary measure. I speculate that the detection device only works on someone with active lycanthropy, which is why Jennifer didn't just buy one and use it to find out for sure whether Wendy was a werewolf. Giving Wendy the DCM hairclip (and perhaps grabbing the detection app) means Jenny can try to be the first to find out if Wendy is a werewolf, and thus inform her daughter of the issue on her own terms.
This doesn't work, of course, if Wendy's first Change is at a sleepover at some other kid's house. Naturally, Jennifer will do her darndest not to let Wendy out of her sight on a full-moon night, but...
Well, that all helps explain why Wendy doesn't transform - it isn't certain whether she inherited lycanthropy from her mom, and the onset of full lycanthropy in a latent victim is unpredictable.
As for the DCM hairclip, I guess that's a precautionary measure. I speculate that the detection device only works on someone with active lycanthropy, which is why Jennifer didn't just buy one and use it to find out for sure whether Wendy was a werewolf. Giving Wendy the DCM hairclip (and perhaps grabbing the detection app) means Jenny can try to be the first to find out if Wendy is a werewolf, and thus inform her daughter of the issue on her own terms.
This doesn't work, of course, if Wendy's first Change is at a sleepover at some other kid's house. Naturally, Jennifer will do her darndest not to let Wendy out of her sight on a full-moon night, but...
From the short story, we can assume lycantrophy is something like a virus; it needs a certain amount of time before the full symptoms (transforming and maybe being able to infect other people with it) can show. And for the incubation time itself was kinda long, starting to the point Jeniffer was bitten to the point that Wendy gotten about 5-6 years. If it was the case, at this time Wendy already gotten infected by the virus, but haven't been completely converted, thus only act as a carrier to the lycan disease without showing the symptoms.
Jeniffer don't need the hairclip-because she's already been exposed as one thanks to the Vampire dad's nose. Her werewolf scent is all over, even after transformation ends. Instead, Wendy would benefit from the hairclip because her werewolf presence has been masked by Jeniffer's scent-unless the vampire has enough olfacionary power to distinguish between two werewolves' of same bloodline scent, she won't be detected as one. Suspected, but not confirmed.