I don’t usually read News Ltd, so I’m afraid I almost missed this story from last week – I only found it because the Conversation yesterday had a piece on the relevant science. But the politics (or ethics) of it interest me a lot more than the science.

Briefly, the Telegraph reports that the state rail authority in New South Wales is planning to test devices that use a very high-pitched “buzzing noise”, inaudible to those over the age of about 24 (whose hearing has lost the capacity to detect high frequencies), to deter young people loitering in “known trouble spots” – who apparently are presumed to be vandals, graffittists or other troublemakers.

The devices, known as “mosquitoes” (read their sales pitch here), are popular in Britain, where high-tech social control is all the rage. But not everyone is supportive. A committee of the Council of Europe recommended in 2010 that “their use in public places should be banned” as “an illegal solution under the terms of international human rights instruments,” although no further action has been taken.

One is compelled to wonder what the reaction would be if the devices discriminated on the basis, say, of race rather than age. It’s not hard to imagine a device that hooked on to a genetic property peculiar to (or significantly more common in) members of a particular race; just such a thing was central to the plot of a 1941 Robert Heinlein novel, Sixth Column. It may not be scientifically possible now, but surely no-one would bet against it being available in the not very distant future.

I suspect such a device might be rather popular in certain circles, offering the ability to keep away Africans, or Aborigines, or some other disfavored group. But would the rest of us be so complacent?

On the contrary, I think it’s safe to predict that race-based “pest control” would produce a gigantic public outcry. It would be said, rightly, that it amounted to racial discrimination of the worst order. Any businessperson trying to market such a device would be lucky to stay out of jail.

Yet is the “mosquito” any different in principle? In each case a particular group is singled out for special treatment – in effect, collective punishment – based on the alleged propensity of some of its members for misbehavior. The difference is that the “mosquito” taps into our deep-seated ambivalence about whether young people really count as fully-fledged citizens. Everyone else has rights, but young people, it seems, only have privileges that can be withdrawn at any time.

Either the places where the devices will be located are open to the public, in which case young people will be prevented from exercising their legal rights, or they’re not, in which case there’s no rational reason to target just one segment of the population.

Is there any other group of Australians that would be treated with such disdain?