I have homes in Texas and California. Many of the items I purchase in Texas, Amazon, and others will NOT ship to California because they are forbidden there. Naturally, before I take any of these items from Texas to California, I check with an attorney, local regulators, and the supplier. Obviously, governments can tell you what kind of tires you can put on your car. The logic behind their tire choices for you is irrelevant. It's common practice for landscapers to go to Nevada and smuggle in forbidden landscaping equipment that they cannot buy in California.