Just as much as it makes sense to us that the kidnapped victims are automatically innocent, it's a thing for them to turn them because they believe our guards are down on that person. But the fact is, they are only innocent on the day they return to us from being kidnapped. I am on the fence of whether the vamps would put themselves out that far by automatically turning those that we would assume is innocent and believing that as a town, we would realistically think they were innocent for the rest of the game. I don't know if they would be so obvious as to choose the kidnapped victims because we knew they were innocent at one point. This situation goes back and forth in my head and I guess it would depend on who the LV and vampettes were as to whether they would go for such an obvious route.
hmmm.... the more I think about it, who's to say the vampires couldn't ask to turn the kidnapped victim on the day they are released back into the town?