Just one more point, which fits the debate.
Prior to the introduction of 900 hour legislation airlines were able to achieve greater productivity from their crew. Indeed many cabin crew were against the legislation as it resulted in the loss of trips and therefore allowances/wages. So the legislation wasn't welcome by either employer or employee, and increased employer costs whilst reducing employee earnings. Indirectly (or directly depending on your viewpoint) the legislation contributed to the need for Op Colombus and new fleet.
From a cabin crew perspective, there was a campaign for an opt out clause, but the company offered no support. As a Police Officer I was legislated by a work time directive, but was able to opt out to allow 12 hour shifts and therefore four on four off work patterns.