I think its been firmly established that double blind tests are fatally flawed..

just a quick scan of the links give ...I can point out at least one failing that will invalidate each of the noble if misguided efforts.

The first is sample size and the second is bias .....

none of the test had enough randomly selected participants ....you need a sample size of more than 50 and these must not be friends or relatives or like minded people....

so thats put that lot to bed.

I've never heard cable directionality......but I don't discount it.  The current scientific thinking makes it extremely unlikely ...but then again if you were the Pope and Copernicus came to you and said I've a new theory about the earth ....would you have called him a heretic ?  [As his current understanding indicated].

I've proved cables can sound different to more that a hundred  listeners [not all at one time]  are they all wrong ?  I've made upward of 50 different types of  cables ..the only directionality was due to a pseudo balanced topology.... or other component additions.  That said I'm happy to accept dirrectionality  can happen, if an organization has the evidence thats ok too ...but it would be nice if they could share it.