In Pierburg GmbH & Co. KG v. Superior Court (1982) 137 Cal. App. 3d 238, a case arising from an automobile accident, the plaintiffs contended that Pierburg could not rely on the Hague Convention to avoid answering interrogatories, because it had voluntarily answered interrogatories propounded by a codefendant without insisting on Hague Convention procedure. The plaintiffs' interrogatories were numerous and inquired in great technical detail about Pierburg's carburetor, whereas the codefendant's interrogatories related solely to the location of photographs of the car involved in the accident. (Pierburg, supra, 137 Cal. App. 3d at pp. 240-241.) The Pierburg court quoted extensively from the two Volkswagenwerk cases (see fn. 1, ante), with particular emphasis on the holding requiring first resort to the Hague Convention. (Pierburg, supra, 137 Cal. App. 3d at pp. 241-244.) The Pierburg court concluded: "In view of these cases . . . no elaborate analysis is needed to conclude that a civil litigant . . . cannot 'waive' the applicability of the Hague Evidence Convention by failing to assert noncompliance with that convention as to prior discovery by other parties to the action.The foundation of the convention is to avoid international friction where a domestic state court orders civil discovery to be conducted within the territory of a civil law nation that views such unilateral conduct as an intrusion upon its judicial sovereignty. The failure of one litigant in the domestic action to demand compliance with the convention cannot divest the foreign nation of its sovereign judicial rights under the convention. The convention may be waived only by the nation whose judicial sovereignty would thereby be infringed upon." (Pierburg, supra, 137 Cal. App. 3d at pp. 244-245.)