You will not find the Law of Unintended Consequences on any statute book in any country but it is a universal law nonetheless, applying to every human action, either well- or ill-intended. Folk wisdom has other names for it, some rude, some not – Murphy’s Law and Sod’s Law come to mind. In the Western Cape we are heading for a perfect example.

Meddle with the economic law of supply and demand (as Cosatu Western Cape provincial secretary Tony Ehrenreich and farmworkers will soon discover) and unforeseen circumstances will surely follow – unforeseen, that is, by those who will suffer and those who led them to strike.

It is an unfortunate fact that the more there is of anything, the cheaper it is. This applies to an oversupply of labour just as much as an oversupply of beans or peas. Minimum wage regulations try to ameliorate this and to some extent they can be successful. The Law of Unintended Consequences strikes when the minimum wage prompts counter action by the market.

Jacking up the minimum wage will result in job losses. As Ehrenreich would have known if he had bothered to check, wine producers elsewhere in the world no longer rely on hand pickers to harvest their grapes. They use machines.

Even in that bastion of tradition, France, wine makers use machines for 60 percent of their grape picking and for the balance they employ family, friends and university students or ex school pupils having a “gap” year before further study.

Australian grape farmers use machines almost exclusively, as do the Americans.

The Law of Unintended Consequences dictates that when labour turns violent, mechanisation follows. Western Cape vineyard owners know about grape-picking machines. They have probably known for ages. After the De Doorns riots and arson, you bet they are getting ready to use them.

No doubt the union leaders and the striking part-timers believe that machines can’t take the place of hand pickers. They think grape-picking machines are too rough for delicate grapes. They are wrong.

These machines are not cheap but with careful planning they can be shared by groups of farmers. Moreover, they are not some new-fangled technology yet to be proved in the field. There are many models, too, the latest being so gentle on the vines that, yes, it may even be possible to use them to pick table grapes.

Using a machine, one team of eight can pick 200 tons in 10 hours. Hand pickers in the US can manage only 20 tons.

Of course, mechanisation is not as simple as just buying a machine. Merlot and cabernet sauvignon grapes are most suitable. Pinot noir is not. The kind of trellis and the contour of the land are important. But mechanisation has its attractions. A mechanised vineyard does not have to worry if labourers don’t come to work. Machines work whether it is hot or cold, rain or shine and even at night. Machines are cheaper than people.

Cue screams of horror from the unions. Yes, it is horrible. Contemplating any increase in unemployment is awful, but that will be the inevitable consequence of recent events. A 50 percent jump in minimum daily wages will mean that to stay competitive on world markets our grape farmers will have to mimic the Australians, the Americans and the French and use machines to survive.

Those who followed the siren song of the Left will be out of work. It’s the Law of Unintended Consequences.

Keith Bryer is a retired corporate communications consultant with wide experience in the extractive industries.