Messiah
You're mixing up two separate events.
The first, in 1995 - was not a "sign or be fired" ultimatum. What it DID threaten (and was true it's word, by the way) that if the officer chose not to sign, there would be no bases, salary increases or type changes for the individual. At that time, there were 18 who chose not to sign. Many of the 18 names reappeared on another list, in 2001.
Without getting long winded about the contract, it was raising the overtime threshold and reducing overtime rates. As it was a deterioration in CoS, it was unenforcable - hence the "option".
The second event, in 1999, was an ultimatum - and ALL eventually signed. It was a nominal "improvement", so the threat could be made. CX management, frustrated after years of contractual impasse, wanted an end to industrial bickering that defined KB's tenure, and presented (not without warning) an improved package - blessed by the HKSAR labour department.
Why the AOA chose to dispute the package was because it wasn't a negotiated deal. The enforcement led to the industrial action it tried to avoid, which led to the disgraceful 49'ers sacking, and all that has followed.
People in glass houses...