In a thread a while back I went off on a bit of a rant about how hi-fi shops often flog ridiculously priced cables, "converters" and other devices for hundreds and sometimes thousands of pounds that are in reality no different in the slightest from their 99p equivalent. The idea of course is to back up these claims with impressive sounding figures on distortion, EMF and the like - however 99% of the time it's complete nonsense.
I brought this up because I found a concrete case in the UK of the ASA completely shooting down a guy on one particular case of it:
...so if you see any similar claims - stay clear! Some of us might see through the blatant sales talk as being complete crap to start with. Unfortunately many people don't, splash out hundreds on a power cable then proclaim to everyone else that it makes a huge difference (you'd look a bit of an idiot otherwise wouldn't you?!) It's a bit of a vicious cycle.
Personally I would've liked to see the above guy prohibited from owning a business rather than just being told not to do it again - it'd make more of an example and hopefully help to stop such behaviour in future. But at least the point has been made.
Of course the bigger lesson here is if a sales pitch makes a scientific claim you don't understand, CHECK it before believing it.