I was off on my numbers, the AFA does not outnumber the IAM represented FAs at CAL by 3:1. It looks like AFA has about 40% more flight attendants represented than IAM: 15,000 at UAL and 9,300 at CAL. That's still enough to win a majority vote in a certification battle.
I hope that the leadership of both unions are talking with each other to find a complimentary solution that address their needs.
More info here:
Continental Reaches Deal With Flight Attendants