Nigel,
They didn't wimp out last time. They had voted yes for PIA and were all set to go. The company then won an appeal in the IRC that if they did strike lives would be in danger because EMS services would be interrupted.
Heliringer,
I'll think you'll find that these days the guys realise they have expensive skills and endorsements(139/225/AS332/76C++) that aren't replaced cheaply. So management doesn't have the upper hand. Management also know that the oil/gas companies are watching them closely and the last thing they want is a disruption to their service.
Why should the lowest paid people on a flight to an oil/gas rig be the two guys up the front?