What offense occurs when a man intentionally tracks his ex-girlfriend without her knowledge?

The offense that occurs when a man intentionally tracks his ex-girlfriend without her knowledge is best described as unlawful installation of a tracking device. This definition aligns with laws that specifically address the unauthorized use of tracking devices to monitor someone’s movements without their consent. Such actions infringe upon a person's right to privacy and can be legally pursued as they demonstrate a clear breach of legal boundaries set to protect individuals from being surveilled or tracked without consent.

While invasion of privacy, stalking, and harassment each describe behaviors that can negatively impact a person's personal space and mental well-being, the specific act of tracking through a device directly involves the unauthorized installation and use of that device, making unlawful installation of a tracking device the most precise classification for this scenario.