[wilhow]

We really can't prevent anyone from copying a design. It might not be the ethical thing to do, but there no real way of stopping someone if that's their goal. However I still wouldn't shame them. I would call them out in a more gracious manner. Something like a list of those companies and title it "Copying is the sincerest form of flattery" or along the same line.

Why not use them to your advantage, use them as marketing tool and if they refuse then force them to remove the design. Maybe only then, at that point it is ok to call them out and shame them.

Shaming someone just created an adversarial effect and it brings some negative publicity too. If you can show that you are gracious and is able to manage and find a middle ground in such a situation, it'll show a better you. I rather work with a company that I can always negotiate with than one who always take the hard line.