If you force them to pay a decent wage, then the workers from developing countries will lose their competitive advantage, losing the jobs to local workers. This means the money remains concentrated in developed countries, instead of raising the wages in developing countries (as it's been happening in e.g. China).

Regardless, demand for cruises is not extremely elastic. Make them more expensive and there will be fewer of them as people make alternative vacation plans. Thus fewer opportunities for poor workers. Not to mention, those workers' competitive advantage is their willingness to work for the lower rates. Take that away, and the lines will start hiring closer to home.

Then there are such questions as where did they get the ships built? At what rates? What type of paint is used? Where does the metal come from?

But even saying that some cruise liner magically appeared from some virgin source of capital - it is somewhat disingenuous to imply that choosing to employ people at what could be considered slave wages is anything but exploitation? It might be called arbitrage if the differences in wages where slight -- but they're not, are they?

I'm sure they got the money from obscenely well paid bankers. What's your point?

But even saying that some cruise liner magically appeared from some virgin source of capital - it is somewhat disingenuous to imply that choosing to employ people at what could be considered slave wages is anything but exploitation? It might be called arbitrage if the differences in wages where slight -- but they're not, are they?

Being arbitrage doesn't prevent it from being exploitative. Bu my point is that this aesthetic approach to public policy is terrible, because it tries to treat the ugly symptom, while making the underlying problem worse.

Yes, they are making a lot of money by exploiting the wage difference. But prohibiting that doesn't solve the problem, which is that some people are poor enough to accept such low wages. If you forbid it, the poor will remain poor just as well.

Now if you take the capitalist approach, the system is working: by performing the arbitrage, the poor people will have employment, more money to spend, etc (e.g. wage rises in China).

If you take, say, a marxist approach, the problem is the core of the system, and small adjustments won't solve it; you need a revolution which will bring real change.

In any case, my point is that these patches are trying to solve the wrong problem, and are not only ineffective but actively harmful to those who we're trying to help.