In People v. Williams (1999), 20 Cal. 4th 119, our Supreme Court, after reviewing the substantive law regarding a defendant's Fourth Amendment rights against unreasonable searches and seizures and the vehicle inventory exception to the search warrant requirement of the Fourth Amendment (20 Cal. 4th at pp. 125-127), explored the procedural requirements of properly presenting a section 1538.5 motion to suppress evidence obtained as a result of a search or seizure. (20 Cal. 4th at pp. 127-136.) The court in Williams held that: "When defendants move to suppress evidence, they must set forth the factual and legal bases for the motion, but they satisfy that obligation, at least in the first instance, by making a prima facie showing that the police acted without a warrant. The prosecution then has the burden of proving some justification for the warrantless search or seizure, after which, defendants can respond by pointing out any inadequacies in that justification. Defendants who do not give the prosecution sufficient notice of these inadequacies cannot raise the issue on appeal. 'The scope of issues upon review must be limited to those raised during argument. . . . This is an elemental matter of fairness in giving each of the parties an opportunity adequately to litigate the facts and inferences relating to the adverse party's contentions." (Id. at p. 136.) In so holding, the court in Williams, supra, 20 Cal. 4th 119, concluded that as with any other motion, defendants making a section 1538.5 motion "must specify the precise grounds for suppression of the evidence in question, and, where a warrantless search or seizure is the basis for the motion, this burden includes specifying the inadequacy of any justifications for the search or seizure." (20 Cal. 4th at p. 130.) The court clarified that the degree of specificity necessary in any particular case "will depend on the legal issue the defendant is raising and the surrounding circumstances," and "need only be specific enough to give the prosecution and the court reasonable notice. " (Id. at pp. 130-131.) The court in Williams cautioned, however, that defendants "cannot . . . lay a trap for the prosecution by remaining completely silent until the appeal about issues the prosecution may have overlooked." (Id. at p. 131.) After reviewing the Court of Appeal decisions on the subject, it noted that the "determinative inquiry in all cases is whether the party opposing the motion had fair notice of the moving party's argument and fair opportunity to present responsive evidence." (Id. at p. 135.) With such principles in mind, the court in Williams, supra, 20 Cal. 4th 119 turned to the facts of that case, which revealed Williams had moved to suppress evidence that police found in closed leather bags seized during an inventory search of the trunk of his car. (Id. at p. 136.) The court noted that Williams had anticipated the prosecution's justification for the warrantless search in that case by arguing in his moving papers that the police had no set inventory search policy. (Ibid.) The court found nothing wrong in such shortened procedure, but cautioned that where the defendant does so, "the prosecution should avoid the 'trap' of simply responding to the defendant's arguments and then resting." (Id. at p. 136.) Because the prosecution in Williams merely argued the officers conducted an inventory of the truck after a lawful arrest, but did not show that there was a written policy or procedure for conducting such inventory search even when faced with moving papers that alleged there was no such policy, the Supreme Court found there was adequate notice given to the prosecution "that it had to prove a policy specifically governing the opening of closed containers." (Id. at p. 137.) The court reasoned that the express reference to "policy" by the defendant and his citing of United States Supreme Court precedent concerning inventory searches which required some written policy or "standardized criteria" governing the opening of closed containers was sufficient to apprise the prosecution "it would have to prove not just any policy, but, more specifically, a policy governing the officer's decision to open the leather bags." (Ibid.) The court in Williams, supra, 20 Cal. 4th 119 did not find it significant that defense counsel did not specifically mention a policy governing the opening of closed containers at the time of the argument in that case because he had already referred to the inadequacy of the inventory search, and under established case law the prosecution is required to prove the existence of a policy supporting any inventory search. (Id. at pp. 137-138.) It further noted that because the trial court had "abruptly interrupted defense counsel's argument in order to make its ruling" on the motion, there was no way to determine whether defense counsel might have made mention of the closed bags if he had been allowed to continue with his argument. (Id. at p. 138.) In addition, the court found the facts of Williams, supra, 20 Cal. 4th 119 a prime example of the police using an inventory search as " 'a ruse for a general rummaging,' " rather than a valid inventory search which adhered to a preexisting policy or practice because the officers had stopped taking the inventory after they found drugs in the closed leather bags in the trunk. (Id. at p. 138.) Based on all of the above circumstances and the law concerning inventory searches, the Supreme Court found the prosecution had not met its burden of showing the inventory search in Williams was conducted pursuant to a preexisting policy and that "the Court of Appeal had erred when it concluded that defendant had waived the issue of whether the opening of the leather bags was pursuant to a policy or practice." (Id. at pp. 138-139.)