I would say a peel off tab covering the code might work so you know it's been tampered with. A few thing could be used to prevent copying. Users could be allow

I would say a peel off tab covering the code might work so you know it's been tampered with. A few thing could be used to prevent copying. Users could be allowed to register a name on the verification page. If you try and register a product and it's already registered you know it's fake. I don't think it would work in every instance. But it would increase costs to the counterfeiter. Hopefully to the point that it becomes economically unsustainable.