I am busy right now but I shall try to dig up the details. What it amounts to is that the law in most EU countries in one way or another does not allow deception in sales. Here was a chain of audio stores that claimed that the cables they were selling were sonically superior. So the UK Consumer Protection Agency (I think it was them) took the stores to court because they could not prove that claim. I think expert witnesses were also called in.
Other groups could have done the same, like consumer organizations (they often do) or consumer tv programs that name and shame.
The store had to withdraw its claim, and without that claim there was little point in selling such expensive cables. Unfortunately this does not mean that things like this will not happen again, and many cases may remain under the radar, but it does mean that sellers have to be very careful with what they claim.