What principle is important to follow to avoid breaching privacy during surveillance?

The principle that is important to follow to avoid breaching privacy during surveillance is that surveillance must not infringe on a person's legitimate expectation of privacy. This principle is grounded in the understanding that individuals have certain rights to privacy, which are protected by law.

When conducting surveillance, it is essential to respect settings and situations where individuals can reasonably expect privacy, such as in their homes, private conversations, and other areas where they are not likely to be observed by others. By adhering to this principle, private investigators can ensure that they are operating within legal boundaries and respecting the personal rights of individuals. Violating this principle could lead to legal repercussions, including civil suits or criminal charges against the investigator.

In contrast, the other options misrepresent the necessary ethical standards in surveillance practices. Conducting surveillance without proper preparation or discretion can lead to noticeable or intrusive actions that may breach privacy expectations. Not informing the subject about the surveillance can raise ethical concerns and may violate local laws or regulations. Similarly, obtaining a written confession is unrelated to privacy principles and could compromise the integrity of the investigation. Thus, understanding and respecting the legitimate expectation of privacy is crucial for ethical surveillance practices.