In Lyman v. Mercedes-Benz, USA, LLC, 2009 WL 143695 (2009), the California Court of Appeal for the Fourth District held in an unpublished decision that the Song-Beverly Act does not protect a dealer who has issued special dealer plates rather than registered the vehicle under the Vehicle Code.  The Court of Appeal explained:

The narrow issue in this appeal is thus whether a vehicle, such as the Mercedes, that displays special dealer license plates (Veh.Code, §§ 11714, 11715), constitutes a “vehicle[ ] … registered … in California [under the Song-Beverly Act].” (Park City Services, Inc., supra, 144 Cal.App.4th at p. 298.) We conclude that such a vehicle is not “registered in California,” within the meaning of the statute.  As described in part III.B.1.e., ante, division 3 of the Vehicle Code establishes a specific and detailed statutory scheme for registering vehicles in California. In this case, it is undisputed that that Lyman did not register the Mercedes under the usual provisions for registering vehicles set forth in division 3 of the Vehicle Code.  Further, as the italicized portion of section 11715, subdivision (a) of the Vehicle Code quoted above makes plain, special plates entitle a dealer to operate a vehicle on the highways “ without registering ” the vehicle. (Italics added.) Given the specific and plain language of Vehicle Code section 11715, subdivision (a), we conclude that vehicles that display special dealer plates do not constitute “vehicles … registered … in California.” ( Park City Services, Inc., supra, 144 Cal.App.4th at p. 299.)