Actually, California has precisely that. Shortly after driving across the California border, you'll usually find an agricultural checkpoint or "Border Protectio

Actually, California has precisely that. Shortly after driving across the California border, you'll usually find an agricultural checkpoint or "Border Protection Station". Their focus is mainly on agricultural products, but they're there to get you to dispose of (plant/animal-based) materials that violate CA law. http://www.cdfa.ca.gov/plant/pe/ExteriorExclusion/borders.html http://www.cdfa.ca.gov/plant/pe/ExteriorExclusion/borders.ht...