The issue is only for HA wearers that don’t have a t-coil setting on their HAs. They only have Bluetooth.
True that only a few HAs have full standard Bluetooth functionality. From what I’ve read it s more common for HAs to have say the HFP and HSP profile enabled only to allow them to receive phone calls and act as a headset. This would bypass Apple tweaked Made For iPhone protocol.
Yes, I could ask the Bluetooth HA wearers to remove their HAs and put on a pair of Bluetooth headphones linked to a standard A2DP streamer at the back but I’m trying to keep it discreet.