My hearing has now deteriorated to the point where induction loops are a Godsend - provided, of course, that the necessary hardware is installed in the dance hall. The proportion of older dancers may have increased over the years - a consequence of people like me dancing for 40 years or more I'm afraid - but I can't see loops being installed in temporary structures like festival marquees. Or am I wrong there - are they used at silent ceilidhs?
The induction loop at C#H is splendid, when it's working. At Halsway Manor it's part of the house P.A. used by the caller, but not necessarily by the band (who usually have their own separate gear). This arrangement has its points.

Incidentally, a separate problem I find with hearing aids is that when the sound level is high, they more or less shut down, and I have to take them out in order to hear properly. This invariably happens in a Sacred Harp singing, or in the middle of a wall of melodeons.