Rather than just the polar extremes of the discussion (IE 1. "union members are commie barstids" 2. "scabs must die"), let me ask for a little more nuanced opinion. Specifically, let me give the exact circumstance that I refer to.
I work for an international company that has a full range of strongly-union to strongly anti-union facilities, varying by location. My own location (Texas) is firmly anti-union. Pay, benefits, employee safety, etc are good and approximately equal at all U.S. locations (I can't compare international locations, because I have no idea what xyz dollars a year will buy you in Brazil or Belgium or Singapore). Non-union locations like mine have better pay in an approximately even trade-off against stuff like more paid holidays (we only get 11 paid holidays, I think our Chicago plant gets four or five more), I don't know what union dues cost, so I can't figure that into the equation.
Anyway, it's a good company to work for and has treated me well for 13 years. I got an email from the plant manager yesterday, of a future possible "work stoppage" at another company location, in a union state. He'll allow ONE person from our plant to go work it if they want to. I've no interest in doing it, but the question got me to thinking of the ethics involved. Do I have a greater responsibility to my employer or to fellow employees in a union state? I know how I feel already BTW, I'm just interested in other people's opinions.
An added factor to the question - if this work stoppage occurs, it could cost me money out of next years bonus. Overall company profitability (among other issues like safety, environmental performance, etc) is an issue figured into our annual "performance bonus" (zero to twelve % of our annual pay). Obviously the difference between zero and twelve % of (let's say for example) 60g in a lump sum check at about property tax time and new lawnmower buying time is significant to most people, myself included.
Now let me throw this open even further to tangents (this thread was intended to be tangent-friendly anyway). I've (like most) two grandfathers, both passed away before I could know them personally, but have from second-hand experience, highest personal regard for both of them.
One of these grandfathers was of the "unionists are commies, and Roosevelt was a dirty socialist" school of thought, and the other was of the "I'm a union man to the bone, and Mr. Roosevelt is gonna save us all " school of thought. I'll let you guess which one was the transplanted-from-Tennessee to the rust belt steel-mill worker and which the New England dairy farmer. Both my parents are a little more nuanced in their opinions.