As well as thinking about the possible threat from inside, ie Openskies, BALPA should also be thinking about the threat from outside that will do more damage to BA terms and conditions than BA ever will!!
The threat comes from Airlines like Lufthansa in Europe and Emirates and other middle east carriers with pots of cash. Wait until they start doing more routes from Europe and as they have already started doing they are bypassing Europe on USA - Asia / Mid East flights so that will eat in to european airlines revenue.
Look at what Ryanair and Easyjet have done to the European market.
If BA don't do this someone else will.