I'm quite sure that people could sign this deal if they wanted as you have suggested Andyismyname. However, it still surprises me that crew feel disadvantaged by not having left the union in time to take up the current offer. After the first opportunity back in the summer people have had more than enough time to make that decision should this situation arise again. If crew have crossed the picket line I really don't see what benefit they feel they have from staying with BASSA when they weren't prepared to support them, do they really think that BASSA will help them if a situation requires it? Even DH has stated that these people will have to deal directly with Unite reps.
I left the union before the first strike because I felt they no longer represented my views and I did not support the action to strike. However, despite my personal views I do not agree with BA discriminating a particular section of it's workforce. The Staff Travel issue alone is IMO on dodgy ground, but deliberately by-passing strikers for p/t and transfers is blatant victimisation. And if this behaviour is acceptable where does it stop?