Well, Federal Way and Auburn, WA have both considered (Auburn has passed) BSL this past week alone. My reaction to it would depend on the ordinance and exactly where it was at. Both cities are close to me, but definitely not affecting MY local ordinances, so I wouldn't have any reason to act any differently (yet). If it happened in my town, it would depend on the law.
For example, Auburn's new law is that all "potentially dangerous" breeds (pit bulls, etc.) have to be registered with the city, no fee. There are no additional restrictions unless the dog attacks, at which point the usual extreme restrictions apply (250K insurance, etc.). I wouldn't own a dog who would pose a risk, so if it were something this simple, I'd stay put, and perhaps send weekly notes to the city council.
I'm joining the ADOA this week (have to mail in my check and app tomorrow), so I'd definitely contact them and any other big wig org. to legally fight it too.
IF a ban occured, grand-father clauses are always included, even in Ontari-hell. I'd have to think long and hard as to what to do. I would spend a ton of energy fighting it, as I described above, but I don't know if I would move. Puyallup is my home, and my entire family lives here. Unless it was a local move to a nearby city that didn't have BSL, I would probably just keep the dogs I had, continue to fight the ban until my dying days, but stay put. My life is here...I just couldn't move away. IF there weren't a grandfather clause allowing me to keep my current dogs, I would definitely move, no questions asked. I would probably be miserable, but I would move, and probably move back after my evil, evil dogs had passed on.
It's so sad we even have to think about this.