Surveillance and Where It Becomes Unlawful

Watching a person from a place the watcher is entitled to occupy is generally lawful. Surveillance becomes unlawful when the method reaches into a space the subject has closed off, when a device is attached to property without permission, or when the following itself becomes a course of conduct the law calls harassment.

The distinction is not about motive. A licensed investigator on a documented case and a stranger with a grudge are judged by the same statutes. What changes the answer is the technique used and the place it reaches into.

The plain view baseline

The starting point is straightforward. A person standing on a public street may look at what is visible from that street, may write down what they see, and may photograph it. There is no general right in American law to prevent being observed in public. Courts have long distinguished between what a person keeps private and what they knowingly expose, and the same reasoning appears in state privacy statutes written for private conduct.

Two qualifications sit on top of that baseline immediately. The first is that the vantage point must itself be lawful, which is the subject of trespass, fences and where an investigator may lawfully stand. The second is that a camera capable of seeing through a window is not doing what the eye does, and several states legislate against exactly that gap.

Devices that do more than the eye

California's civil statute is the clearest model. It creates liability for physical invasion of privacy, where a person enters land or the airspace above it to capture an image or recording of private activity, and separately for constructive invasion of privacy, where no trespass occurs but a device is used to capture something that could not have been obtained without one. Amplifying equipment, long lenses and drones are all caught by the second branch when they are pointed into private space.

Audio is regulated more tightly than video almost everywhere. Federal law prohibits intercepting a wire, oral or electronic communication, and defines an oral communication by reference to whether the speaker had a justified expectation that it was not being intercepted. A parabolic microphone aimed at a conversation inside a house is an interception on any reading. Bugging a room the investigator has no lawful presence in is both an interception and, usually, a burglary.

Tracking devices

Attaching a device to a vehicle to determine where a person goes is treated as its own wrong, separately from any trespass involved in fixing it. California prohibits any person or entity from using an electronic tracking device to determine the location or movement of a person, with exceptions only for the registered owner, lessor or lessee who consents, and for lawful law enforcement use. A violation is a misdemeanor, and where the violator is licensed under the professions code it is also grounds for board action against the license.

Other states reach the same place through stalking statutes, computer trespass provisions or vehicle codes. The safe reading for any operator is that a tracker on a vehicle the client does not own or lease is unlawful, and that a client's assurance about who owns the car is not a defense. Written proof of the client's interest in the vehicle is the minimum any competent file contains.

Software installed on a phone or a laptop raises the same issue with sharper federal consequences, because it usually involves both an interception and access to a protected computer. Location sharing that the subject switched on themselves is different in kind from an application installed without their knowledge. Where the data has to be pulled from an account rather than observed in the street, the question stops being one of surveillance and becomes one about obtaining records without pretexting.

When following becomes harassment

A single observation is not a course of conduct. Stalking and harassment statutes generally require a repeated pattern directed at a specific person which would cause a reasonable person to feel fear or serious distress. Surveillance can meet that description even where each individual act was lawful, and courts have not accepted an investigative purpose as an automatic answer.

Three features tend to push a file across the line: the subject notices and asks the follower to stop; the following extends to a child, a workplace or a place of worship; or the conduct is accompanied by contact, gifts, messages or approaches. Any competent operator treats the moment the subject notices as a decision point, not a challenge, and documents what happened next.

Protective orders complicate this further. Where an order already restrains a party from approaching a person, surveillance conducted on that party's behalf can be treated as an indirect breach, and courts have not been sympathetic to the argument that a hired third party is outside the order's terms. An operator who is not told about an existing order is still the person standing in the street when the police arrive, which is why a written instruction naming any order in force is a standard part of a file rather than a formality.

What a violation costs

Three exposures run in parallel. There is the criminal charge, which in most of these categories is a misdemeanor but can rise where a device or a dwelling is involved. There is the civil claim, which under statutes like California's carries enhanced damages and disgorgement of any proceeds from the material captured. And there is the licensing board, which can act on the conduct whether or not the other two ever conclude.

There is also the evidentiary point, which clients care about most. Material obtained unlawfully invites a motion, a fight about admissibility and a witness whose credibility has been damaged before the substance is reached. A file built inside the limits set out in what an investigator license does not authorize is worth more to a client than a spectacular one that cannot be used.