From the comment section of Who does Dick Cheney think he’s kidding?, posted on The Writing on the Wal:

Let’s even assume that some workers are pressured to sign cards and a place becomes unionized. What’s the harm? The employee is forced to join the union (or not depending upon the laws of the state), but will also get the benefits. If the union does a poor job of getting improved benefits then it won’t last. So the objections (from anti-union lawyers, not so much from workers) are that some will lose some of their libertarian rights and ability to be free-loaders. This is not really too much of an injustice.