concurring specially: I agree that RSA 570-A:l, IV(a)(l), which exempts telephones used “in the ordinary course of [the subscriber’s or user’s] business,” embraces extension telephones used *348in the home. However, I disagree with the majority’s espousal of an unconditional exception for such extension telephones.
Federal courts considering eavesdropping in commercial settings regularly engage in ease-by-case analysis in evaluating the ordinariness of a particular instance of telephone interception. See, e.g., Watkins v. L.M. Berry & Co., 704 F.2d 577, 582-83 (11th Cir. 1983); Briggs v. American Air Filter Co., 630 F.2d 414, 420 (5th Cir. 1980); Campiti v. Walonis, 611 F.2d 387, 392 (1st Cir. 1979).
I see no rationale for employing a case-by-case analysis in commercial but not domestic settings. See People v. Otto, 831 P.2d 1178, 1190 (Cal.), cert. denied, 113 S. Ct. 414 (1992). Thus, I would reject a general approach that would permit eavesdropping in domestic settings, regardless of the particular circumstances. Instead I would consider whether the participants to the overheard conversation had a subjective expectation that their discussion would remain private, and whether such expectations were ones that society deems reasonable. See RSA 570-A:1, II (1986); cf. State v. Lamontagne, 136 N.H. 575, 579, 618 A.2d 849, 851 (1992) (legislature intended RSA chapter 570-A to protect right to privacy); Kratz v. Kratz, 477 F. Supp. 463, 476 (E.D. Fa. 1979) (Title III protects right of privacy in domestic context). I believe that reasonable expectations of privacy distinguish extension telephone uses that may be viewed as ordinary from those which are unacceptable “in a society that values and seeks to protect conversational privacy.” J. Carr, The Law of Electronic Eavesdropping § 3.6, at 3-105 (1990).
Here, the victim lacked a single, consistent caretaker. At fourteen, the victim had stopped living with her mother. She resided with her grandmother for approximately a week before moving to a shelter for girls. The victim remained in the shelter for approximately two months before becoming the defendant’s foster child. Carter and her husband had known the victim all her life. The victim had visited frequently with the Carter family and often had celebrated holidays at their home. Under the circumstances, the victim should have expected that Carter, an old family friend, would assume the role of guardian during the victim’s visit.
Moreover, Carter’s eavesdropping was limited in both purpose and time. She did not record the conversations. Her eavesdropping was not part of a general practice of monitoring telephone calls in her home. Carter had specific, well-founded suspicions about the defendant’s relationship with the victim, and she eavesdropped only out of concern for the victim, a minor temporarily residing in her home.
A person who has illicit sexual relations with a minor cannot reasonably expect that the minor’s caretakers will not try to obtain information concerning the minor’s welfare by eavesdropping on potentially revealing telephone conversations. Accordingly, I would find *349that Carter’s eavesdropping occurred “in the ordinary course of [the subscriber’s or user’s] business,” and that RSA 570-A:6 (1986) did not prohibit the admission of her testimony at trial.
BATCHELDER, J., joins in the special concurrence.