How have the courts treated the issue of consent in the context of search and seizure during a preliminary hearing?

1 That defendant's consent was not in fact free and voluntary was raised at the preliminary hearing. This objection was preserved in his stipulation to the use of the transcript of the preliminary hearing at trial. He also renewed this objection on his motion to set aside the information (Penal Code, 995) with the further elaboration that there can be no valid consent without one being apprised of his rights under the Fourth Amendment. Upon denial of his motion, defendant applied for a writ of prohibition (Penal Code, 999a). The appellate court dismissed his petition because of procedural error without reaching the merits. He renewed his objections at trial, citing United States v. Blalock (E.D.Pa.1966) 255 F.Supp. 268.