If you do not trust your friend, then unfriend them on facebook. Or sue them. If said friend takes a pic of you and records everything you say in real life and

If you do not trust your friend, then unfriend them on facebook. Or sue them. If said friend takes a pic of you and records everything you say in real life and gives that to researchers (or "pro Trump" people), you wouldn't go after your or their landlord claiming they "allowed this to happen", nor would you go after the city where it happened, would you? (your friend is voluntarily participating, knowing what they are doing) Now if the researchers tricked your friend into giving them information about you somehow, then you'd go after your researchers. But do not expect your landlord to go after those researchers for you. (NYU researchers misinforming participants about the scope of their data collection) Now if your friend abused a camera that was sneakily installed by your landlord to obtain that information, then you might go after that landlord (Cambridge Analytica on Facebook)