If Unite allows a strike without the offer being put to the whole membership it will completely destroy whatever is left of the relationship between BA and Unite. Hopefully it is just posturing.
Perversely, this could play into BA's hands if BASSA thwarting a deal prompts a wave of resignations from BASSA and a very poorly supported strike will leave members with nothing. No pay deal, no full staff travel, no facilities agreement and no agreement on Mixed Fleet.