"obligated" That's a good question and I guess it all depends on which side you stand on: Union A (AA) or Union B (TWA). If you stood on Union A in a system where performance means nothing and merely being a number (in seniority) is all that matters then yes, you don't want the blend. If you're a pilot with 15 years’ experience at TWA and now your number is lower than guys with 1 year experience... well, that's a different story isn't it.

It is this very seniority issue that prevents crew from being able to "shop" competitively for their workplace; frankly they’re stuck where they are. Here is a prime example where union "protection" turned into union oppression.