No one said it was only audible to hearing aids. But the customer knew it was her hearing aids and not a loudspeaker in the store.
Neither the audiologist nor apparently the customer knew anything about LE Audio so it was a surprise, as it was told to me.
I forget which supermarket it was. I have a feeling it was Lidl, but it was one I never use anyway, so definitely not Tesco, Sainsbury or Waitrose. I imagine that this was a trial installation of Auracast in a few stores, of which this was one.