Milwaukee is among a number of cities where McDonalds was targeted. Walking of the job isn't a strike; it's walking off the job. McDonalds should feel free to fire anybody who takes part in this effort. If you don't like your working conditions find another job. I'm guess Micky D's would have no trouble replacing these workers.
I realize McDonald's doesn't want to risk the negative PR of firing those who walk off. But cowering to that fear allows this movement to grow. For those who are unaware, take a look at what happened to Palermos Pizza of Milwaukee. A friend of mine in the radio business has what he calls his wheelbarrow of manure principle(okay that's not exactly what he calls it). The point is as long as your talented enough and valuable enough to keep pushing your own wheelbarrow of manure(the pain in the butt you are to management) you're okay.
Could I get away with walking off the job for a day in protest? I'll tell you what; I'm pretty valuable to this company and I wouldn't risk it. If you flip burgers and ask me if I want fries with that for a living you better be pushing a very small wheelbarrow of manure.