This kind of story involves serious unethical elements. Locking someone is a form of imprisonment and coercion, which violates basic human rights. And any form of non - consensual sexual situation is sexual assault, which is completely unacceptable in an ethical and legal society.
One possible reason could be that she was kidnapped by a criminal who wanted to keep her hidden for ransom or other malicious intentions. Another reason might be that she was being held captive by someone with a mental disorder who had an abnormal obsession with her.
No. Locking someone in a chastity belt, even in a story, is a form of extreme control and violates a person's basic rights to freedom and autonomy over their own body. It's not an ethical behavior regardless of who is doing it to whom.
I don't think it's true. Most of the time, stories like this are made up to capture people's imaginations and don't have a basis in real events. They might draw inspiration from various sources but aren't factual.
Probably. Since it's a ghost story, it has a high chance of being scary. Ghosts are often associated with fear and the unknown, and a girl locked in a room with a ghost sounds like a recipe for a spooky tale.