When I was a rep, our main concern was to ensure that we were correctly staffed. We rarely were, especially in the summer months when the air traffic was at its' peak. In order to keep pressure on management, we negotiated an overtime rate that was prohibitive unless they were desperate. Much as I support the union's stance,they have to decide on their principles and priorities. If they're coming from a safety standpoint, you would never want tired or fatigued staff carrying out safety orientated tasks like driving trains,track maintenance or in my industry controlling or piloting planes. Full staffing should be the union's baseline, as it seems to be when it comes to redundancy but, if you're right apparently not necessarily when it comes to overtime.