Yes, they're still in charge of the said app that they are "distributing". Authorization is what matters, it doesn't matter how they're doing it. In this case,

Yes, they're still in charge of the said app that they are "distributing". Authorization is what matters, it doesn't matter how they're doing it. In this case, the users are using an "unauthorized" app and Facebook can block the app if they figure out how to ban them. Facebook can also block the users for using it as well.