Based on the fictional portrayals of private investigators found in cinema, one could easily misinterpret what type of information is accessible to investigators. One of the common misconceptions is that an investigator can easily gain access to telephone or cell phone records.
The reality is that obtaining phone records was rather easy in the past. Any individual, including private investigators, could gain access to records via online vendors by falsely identifying him/herself and paying for the service also known as pretexting. However, this simple procedure was spurned in large part as a result of the 2006 Hewlett Packard scandal in which HP hired private investigators to determine who inside the company had leaked confidential information. Upon using pretexting to figure out the source of the leak, the investigators were criminally charged.
Subsequently, the Telephone Records and Privacy Protection Act of 2006 was passed making fraudulent attempts at obtaining customer information from phone companies a federal offense. Of course, as is the case in any industry, there are investigators that will attempt to and possibly succeed in getting information through an illegal means. However, it is important to remember that individuals who frequently bend or break the rules often lose sight of where to draw the line. This can lead to them providing unreliable and unethical results, not to mention that they will not be seen as a credible source when testifying in court cases.
On a separate but related note, while the use of phone records appears at first to be an excellent asset in proving marital infidelity, is it really the best type of evidence? While phone records can document that an interaction occurred, without proper context these records are ambiguous and have little value. In our experience, a cheater will continue to deny until they are caught red-handed. Therefore, video/photographic surveillance is the only method which casts aside ambiguity and serves as a better, more accurate means of evidence.
http://en.wikipedia.org/wiki/Telephone_Records_and_Privacy_Protection_Act_of_2006