I'm a small business owner and have dealings with unions. As a business owner, about the worst thing you can do is sign a union contract, I know, I've done it. My shop is currently a union shop. I'm sure GM could write novels about the pitfalls and head aches involved.
Unfortunately, labor unions have become unrealistic and out of touch with reality. In the end they do more harm than good for the workers they represent. They end up driving more jobs away than it is worth for the ones they struggle to keep. As much as the management at many US companies needs shaking up, this goes about x3 for the labor unions.
"Beer, the cause of and solution to, all of life's problems." -Homer Simpson