The only option immediately open to the crew is to have the individual removed from the aircraft if they refuse to comply. Problematic if the aircraft is no longer on stand and/or the airbridge/stairs are gone. Unfortunately, it's probably not going to happen unless the circumstances deteriorate and the passenger becomes actively disruptive or aggressive.
I'd be comfortable with passengers being banned for refusing to wear one without good reason. However one imagines BA would like to avoid the negative publicity associated with getting it wrong and offloading/banning a passenger with a hidden disability.
Realistically I don't see what choice the crew have, unfortunately. Cancelling the return ticket might however also send a message.
Last edited by Bohinjska Bistrica; Jan 5, 2021 at 6:39 am