While there is no current law for the spoon, let's swap to a different utensil.
Example, does the store get fined for selling a butter knife if it ends up being a murder weapon? Perhaps they cpuld be done for assisting if they *knew* it was going to be for such a purpose.
But, if used properly, which was its primary design, it's a tool for a job that's legal.
I could understand companies being prosecuted if they advertise their products for being road legal if they in fact, are not. Possibly, but not necessarily, the tuners for tuning a car to a non legal fashion(emissions), but there is always the possibility that the customer really doesn't intend to use the car, in that configuration, on the road. So long as the companies can prove they have conveyed how illegal it is to use the now illegal car, in a place where the vehicle must meet the laws, they shouldn't be punished.
Not sure about other countries or states, but I've been made aware that I can't legally stop a client from taking and driving their own car in NSW, Australia, even if they owe the shop money. It must go through court to get the funds from the customer, and you need to get the police or roads covering body representatives to come and stop the owner from driving the car, even if I know how hazardous the vehicle is.