The choice WAS yours!! Short term financial gain for long term future of a month of stand by, SR, LS & ML must love LM (nearly as much as the CC89 reps who advised you all so well)!!!!
So much for roster stability, I hope you realise that during the month of standby you have NO guarantees of any income or trips!!! Basic (basic being the operative word) pay is obviously enough to live on. Also seniority won't be taken into account, so look forward to Xmas & New Year standby too!!!!!
Still better luck next year, you've really shown the management what your made of (but don't think that the standby will be up for negotiation, you've said yes for good).