Sure I'll hold the line. Call your all your reps and tell them this is what I want then, at minimum, in writing:

-Longevity if I lose my job or if a merger takes place
-Longevity pay or better
-Choice of base/equipment
-Travel benefits equal to your mainline partner (for my commute)
-Any provisions of my current/future contract that were/are superior to yours.

Now that would be holding the line and looking out for each other. If not, you are asking me to take a bigger gamble than I'm willing to take. If you want change, you need to plan a little better on how to take care of your brothers and sisters that join your cause, if the worst case happens to them.