"Also as well as the other problems detailed with bidline, the real cost to the company is all work is not guaranteed to be covered. "
Actually that couldn't be more wrong...the FUNDAMENTAL priciple of bidline is that the pilots undertake to ensure the flying programme is covered. That is pretty much page 1, rule 1 of the BALPA/BA/BIDLINE book. True, occasionally force draft has been used but that is actually within the rules, which guesss what?...is to cover the work!
There is NO way BA will pay for a cabin crew bidline system but they would probably be willing to give Carmen a go on WW. I bet the BASSA reps who have been using/abusing the derostering system wouldn't like to see it's introduction though. go figure :-/