Nah that cant be the reason. They had sex there countless times without the curtains drawn. And theres a balcony outside. You cant see a thing from outside considering how far the bed is away from the window.
I know thats not against the rules but for me its annoying making the view worse (NV is worse than daylight or light. Think we dont need to argue abt. that) on purpose. Being the only appartement doing this it makes them look bad compared to the others and in the end cost them views. Especially now when there are more and more appartements with very good lighting coming online.