In Wilkins v. City of San Bernardino (1946) 29 Cal.2d 332, the California Supreme Court agreed that spot zoning exists when the spot receives either more or less restrictive zoning, although the opinion implies that only the application of more restrictive zoning is problematic:
"So-called 'spot' zoning results in the creation of two types of 'islands.' As pointed out above, the objectionable type arises when the zoning authority improperly limits the use which may be made of a small parcel located in the center of an unrestricted area. The second type of 'island' results when most of a large district is devoted to a limited or restricted use, but additional uses are permitted in one or more 'spots' in the district. It is the second type of 'island' that is presented in this case, and if there is any discrimination, it is in favor of the 'island' since it may be devoted to a greater number of uses than the surrounding territory. It is clearly within the discretion of the legislative body of the city to determine whether such an 'island' should be enlarged or not, and the mere fact that the owner may enjoy greater benefits, or that his property will be enhanced in value, if the size of the island is increased, cannot entitle him to compel the allowance of such increase in size." In Wilkins, the city had twice denied a property owner's request that his property be rezoned from single-family residential to business. (Id. at pp. 334-335.)
The trial court, in ruling on the property owner's declaratory relief claim, determined the zoning ordinance was unconstitutional as applied to that property owner, and enjoined its enforcement against him. (Id. at p. 334.)
The Supreme Court reversed the judgment, and set forth two clear rules of law applicable to challenges to zoning decisions.
First, "the courts cannot write the zoning laws and cannot say that the legislative body has erred in drawing the lines of the districts, or in restricting the territory devoted to business or to multiple dwellings, unless there is a clear showing of abuse of legislative discretion ... ." (Wilkins, supra, 29 Cal.2d at p. 339.)
Second, "where it is claimed that the ordinance is unreasonable as applied to plaintiff's property, or that a change in conditions has rendered application of the ordinance unreasonable, it is incumbent on plaintiff to produce sufficient evidence from which the court can make such findings as to the physical facts involved as will justify it in concluding, as a matter of law, that the ordinance is unreasonable and invalid. It is not sufficient for him to show that it will be more profitable to him to make other use of his property, or that such other use will not cause injury to the public, but he must show an abuse of discretion on the part of the zoning authorities and that there has been an unreasonable and unwarranted exercise of the police power." (Id. at p. 338.)