Grauniad:

I first heard this
alternative history from Derick Thomson, the Gaelic poet and professor
of Celtic studies, who spoke with bitterness of the Highland regiments
as "cannon fodder". The regiments were raised in the 18th century,
mainly as a way of helping to pacify the Highlands. The threat posed by
the clans was removed by recruiting regiments and putting them in the
front line – the Black Watch suffered 50% casualties at the Battle of
Ticonderoga in 1758 – or sending them to disease-ridden places such as
the West Indies.
School textbooks lauded
the bravery of the Highlanders in General James Wolfe’s battle for
Quebec in 1759. Less often recorded is Wolfe’s disdain for his own
soldiers. Reflecting the British government view, he wrote: "They are
hardy, intrepid, accustomed to a rough country and no great mischief if
they fall." And fall they did, in large numbers, the deaths of so many
men contributing, along with the Clearances, to the depopulation of the
Highlands that persists until this day.

Were our ancestors really that clever?

Update. Further thoughts, for this to be true the death rate amongst Highlanders who served must have been higher than that amongst those that did not. Do we know what the death rate from violence amongst the Clans was? Given what we know of that number amongst modern day clan based societies (by far the leading cause of death amongst men), well, I don’t know the answer but an interesting question all the same.