A pretext interview is getting information by pretending: a fake identity, a fake purpose, or refusing to say who you are. It is the insurance version of a con, and California bans it with one narrow exception.
Definition (Ins. Code §791.02): a pretext interview is an interview in which a person, to obtain information about another person, pretends to be someone else, misrepresents the true purpose of the interview, or refuses to identify himself or herself.
The rule (Ins. Code §791.03): pretext interviews are banned, with one exception:
It must be part of investigating a claim where there is a reasonable basis to suspect criminal activity, fraud or material misrepresentation.
Even then, the source may not have a privileged relationship with the person, such as the person's physician or attorney.
Apply it:
Posing as a survey taker to question a suspected claimant's neighbor: allowed.
Posing as a nurse to question the claimant's physician, or as a paralegal to question the claimant's attorney: not allowed, because of the privileged relationship.
Posing as a lender to question a new applicant's employer: not allowed, because underwriting is not a claim investigation.