Yes, if you ever want to see mechanics get what they should be getting we have to be able to move about as freely as possible. Right now, due to seniority, workers race to the bottom with the hope that the carrier where they have seniority survives. Transfer of seniority should be at the mechanics discretion, not the company, however under Southwinds line of thinking your fate as far as seniority lies with the actions of the company.
Look at it this way, I'll use observations from AA. At EAL the IAM represented mechanics took on the company and said no to any more concessions, they struck, the company went bankrupt and eventually liquidated. The stance they took benifitted all airline mechanics but when these warriors of the labor movement got hired by other carriers they started at the bottom, several years later TWA went bankrupt for its third and final time, however its IAM represented workers had agreed to every concession that management asked for, the company milked concession for another 10 years and over those years they helped drag down the whole industry, they helped lower standards, now you are saying that these guys should be rewarded with something that the labor movement fought for-seniority rights, even though for at least a decade they dragged down standards, and the EAL workers should step aside to let them claim that reward.
You have to remember that seniority is a union concept that was fought for and established by Unions. We should not allow seniority to be used as a weapon to lower wages and benifits. Unions should not allow workers to be penalized for fighting against concessions and should not reward those who agree to them at the expense of putting us all in a race to the bottom.
The arguement that "If I quit I should not get my seniority but if my employer gets bought by another company I should" basically says that the company should control your career, not you, and not your Union, that your seniority is a company priviledge granted to you by the company for your years with them and not a union right. It strenghtens the companys bargaining position and weakens the union members bargaining position in several ways.
The concept of tieing seniority to a company instead of your profession was perhaps the industries biggest coup, it basically leaves your carreer up to the chance that you pick the right company, and it stays that way for your whole career. Even at SWA, you could, through no fault of your own, one day see a new management team take over and run it into the ground, and you could be the one who is 55 to 60 years old starting all over at another carrier at the bottom. They know this, and they use it to their full advantage. While having portable seniority will likely never fly what we should concentrate on doing is getting rid of all progressions. Pay rates, vacations, holidays etc, everyone should be on the same page. Maybe a stipend for longevity but thats it. At least then you would not see mechanics with 20 years starting at entry level pay way below what a mechanic should be getting.