What is your view or opinion on this? Please see below.

First and foremost important restriction in conducting surveillance is not to alert potential perpetrator. If perpetrator gets sense of ongoing investigation, then they can hide or destroy evidence. They might get cautious. That is why surveillance must be conducted carefully and confidentially. Another important thing is "Existence of Fraud Predication". This is the base of investigation approach. Without proper predication, surveillance or any other investigation technique can not be conducted. Surveillance is normally legal as long as it does not invade a person's reasonable expectation of privacy under the fourth amendment to the constitution. Fourth amendment protects the right of a person against unreasonable searches. Also any fraud investigation must be approved by management and especially surveillance of potential perpetrator must be informed and management's consent must be obtained before it begins.