It's not the regionals that whipsaw each other, it is the majors that cause the whipsaw to occur. An objective viewpoint here, or at least an attempt. Foreign carrier entry into the US market would be bad for the majors. The foreign carriers would do it cheaper because they would not be held to the same standard (i.e. operating cost), as their US counterparts. Therefore, over a period of time US majors would be forced to do one of two things. Move their business overseas or close the doors. No idea how long that would take.

Other side of the coin viewed by regional pilots and it has been stated previously. A regional pilot (FO) topping out at $45K a year looks at a foreign carrier willing to pay $60-80K a year as a definite improvement. If foreign carriers were allowed to operate in the US (cabotage), there would be a mass exodus from the regionals to the foreign carriers. I would not look down upon anyone who did so.
It would behoove all pilots to take a good look at what is going on in the regional industry and make an attempt to fix the payscale which is the primary driver of this thread. The guys at the majors (the ones still 20 years out from retirement) should look at what the possibilities are for their future employment. Help get the industry on both the regional and major level fixed.