--they are heavily exploited, certainly, especially given the sectors that they are prominently employed in by foreign and domestic capital. I wouldn't deny that. Of course there is a whole lot of investment in China that is not in labor intensive sectors, a whole lot, and there the whole picture is far more complex. However I think that vulnerability is raised even further by the WTO provisions that will make it easier to drive out local state companies subjected to private competition and that will enable foreign companies to invest in plants in China to produce goods for the Chinese markets, the ultimate goal of big captalist investors in China in any event. And it's complex in any event. Most Chinese workers I knew in the state sector would die to get a job in the foreign companies, but they can't since they're too old (i.e. over 30). They're more interested in the rural migrants and/or younger workers from the state sector companies that bring skills and higher education levels. Those younger workers often enough think they're making out great compared to state workers, unless they're in a more labor intensive sector of course.
I see the unemployment problem in the state sector as one that plays a much bigger role in pulling down Chinese wages actually, which is closely correlated to the pressures WTO, loosening of capital controls, privatization trends, and the like put on Chinese state workers. The whole slave labor business just misses this, it's not as sexy, nor politically popular in the US to discuss privatization's impact on workers in developing countries.
I wish I could answer your question more fully, but I'm getting ready for a flight to Honolulu tomorrow for my defense...so I'll have to defer to the eminently (and in fact more) qualified Mr. Lassen to pick up from here for me.
btw, i posted something to the pen list a few years back, written by barry shepard that is one of the best written left response to the anti- china trade position:
http://csf.colorado.edu/pen-l/2000I/msg02453.html
also by Bill Tabb in March 2000 Monthly Review http://monthlyreview.org/300tabb.htm
"The use of trade sanctions to enforce labor standards is also opposed by most third-world unionists, who see job loss resulting without necessary impact on their wages and working conditions. What they need is help organizing. International solidarity, exposure of local abuses, financial assistance to strikers, and pressure on governments who use police-state tactics against workers would be welcome. But the fact is that, in the past, the United States has supported the most repressive third-world regimes. People are rightly skeptical about Clinton's motives. The solidarity which needs to be extended is to the workers, oppressed and exploited not simply by transnationals, but by their own capitalists. Rather than counting on the kindness of passing imperialists, a class struggle perspective is in order. The same is true in making common cause with reactionary Republicans who wish to weaken China for their own reasons."
http://monthlyreview.org/300tabb.htm