I would be very wary of advice from BASSA's lawyers. They (as with BALPA's lawyers over Openskies) don't have a great track record against BA's lawyers.
Completely agree. BA will have checked this all out very thoroughly with their legal department months ago. Same goes for staff travel. BASSA, if they had any brains at all, would have done likewise.
It's yet another example of how BA are controlling this process and BASSA are, well, er, not.