What is the legal argument that a temporary detention is necessary to protect the privacy of a person who has been questioned by the police?

1 This somewhat startling statement, which seems to justify one invasion of privacy by reasoning that, were it not permitted, the police would commit an even more serious one, is probably just a compendious way of stating the rationale of People v. Mickelson, 59 Cal.2d 448, 452, 30 Cal.Rptr. 18, 380 P.2d 658 that the recognition of the right to effect temporary detentions for questioning 'wards off pressure to equate reasonable cause to investigate with reasonable cause to arrest, thus protecting the innocent from the risk of arrest when no more than reasonable investigation is justified.'