So how many turn backs were there last year? What was the fate of those ships en route? What was the fate of the people once returned to the place they were fleeing? If you know any of those facts, please share, since the Government isn't. And that is just the start of what we would need to know to say that locking up kids is preventing deaths (which no longer really happens, incidentally, thanks to some Liberals having pangs of conscience about it, after organisations like Medicine sans Frontiers highlighted some of the troubling things that were happening, despite members facing legal penalties in Australia for breaching laws set up to hide away any issues. I'm guessing when they learned of what senior people like ScoMo were doing, they too thought it was vile)
What we do know is that locking up kids is a pretty terrible thing to do, especially for long periods, especially kids lacking education, resilience, social capital, and language skills needed to cope. So we would want the case to be pretty convincing that it is preventing deaths (and even then there would be cause to question if that is how we want to conduct society, in strictly utilitarian terms).
There are workable solutions throughout the world, with really only a handful of modern, western democracies resorting to locking up children.
The burden of dealing with most displaced refugees (about 85% of them in recent years) falls on developing countries. In those cases the refugees, children and all, often do live locked up and in terrible conditions. But countries that have many, many refugees, like Bangladesh, that are also very poor and have plenty of citizens living poor lives, don't have the resources to offer much better to hundreds of thousands of refugees. And despite the poor conditions, refugees still pour in, as living a bad life, taking risks to get there, is still often better than living somewhere where a militia may come at night and slaughter your family and pass you around for rape if you are a girl over about 8.
We have the resources to do more than lock those kids up, and we have no evidence that locking them up did anything to reduce the deaths of people (who often would be pretty desperate to flee even if they would be locked up, as Bangladesh and Thailand, for example, show). It was cheap political point scoring, which is obvious because we are now doing "workable solutions" that don't involve locking children up (well, depending on definitions, some would disagree). I still can't believe anyone with humanity would endorse punishing children like that for cheap political point scoring, but obviously the solution is "0 boats, 0 deaths"....