I can see imposition just around the corner. The cabin crew then strike, go sick or whatever. The first 2000 to do so are sacked - people will soon think twice about not showing up for work, and now no Voluntary redundancy is required.
If the sacked crew win an employment tribunal, BA simply pays them the minimum compensation they can get away with (it will still be less than the currently proposed voluntary redundancy pay). Plus I bet many would not win their case, because there has been so much talk of 'bringing down the company' that the tribunals would be on BA's side.
BA loses its 2000 most militant crew, and ends up with the crew on even worse terms and conditions than are currently being proposed. ie BA win, and the crew LOSE.
I think it is time you all started begging your reps to negotiate.