jimd-f
one of the crucial points to consider, of such an offer, is that it is not enticing people to leave the union, as that would be illegal.
I could see BA doing this again, for the reasons you state, but it would be with a back dated point where the employee must not have been part of the union.
If they were to do this again it could be interesting, as I could see BA then having a fair number of staff "on-side" with the new contract, pay rises, guarantees etc... there would then be nothing to stop it terminating all existing LHR Worldwide and LHR Eurofleet contracts, and re-signing on new (worse) terms.
That would be an ultimatum to all staff - either accept the contract, or bye bye... you cant in all practicality sign the new contract then strike... can you?!