McGrath, I appreciate your points. However, as I see it, there is considerable difference between a slave who was captured from his home and transported for a lifetime of manual labour, and an intending illegal immigrant who takes a chance that a criminal 'fixer' wont treat him too badly.
The people doing the dumping at sea would be thugs hired by the fixer, who would himself be 'innocent' if not beyond reach of the law in his own country.
There used to be a legal definition called outlawry, where people that the law couldn't reach were tried or declared in their absence and stripped of legal protection Primitive, but there are a lot of people deserving of it today.