I've been watching this with interest. I have a work trip to the US in the autumn that I may not be permitted entry to travel for. Currently BA and VS have availability for what will be a busy route I'm sure. I've been waiting to see what the BWC rules would be. As I understand it as of now any cancelled trip will result in a voucher that must be spent on flights taken before 30/04/22? Similarly for date and route changes? So If I had to cancel a November trip I would need to both spend the voucher and use the replacement flights before the end of April next year?

edit - I think CWS posted as I was writing to confirm this