Increased duties, especially those on wines and spirits during the late 18th and early 19th centuries resulted in widespread smuggling and it was found to be successful because the customs officers found it impossible to police, and also because of social approval.
Rudyard Kipling's 1906 A Smuggler’s Song shows us exactly what was going on in nearly all Cornish ports at this time.
Don't go drawing back the blind, or looking in the street,
Them that ask no questions isn't told a lie.
Watch the wall my darling while the Gentlemen go by.
Five and twenty ponies,
Trotting through the dark -
Brandy for the Parson, 'Baccy for the Clerk.
Laces for a lady; letters for a spy,
Watch the wall my darling while the Gentlemen go by!
Running round the woodlump if you chance to find
Little barrels, roped and tarred, all full of brandy-wine,
Don't you shout to come and look, nor use 'em for your play.
Put the brishwood back again - and they'll be gone next day !
If you see the stable-door setting open wide;
If you see a tired horse lying down inside;
If your mother mends a coat cut about and tore;
If the lining's wet and warm - don't you ask no more !
If you meet King George's men, dressed in blue and red,
You be careful what you say, and mindful what is said.
If they call you " pretty maid," and chuck you 'neath the chin,
Don't you tell where no one is, nor yet where no one's been !
Knocks and footsteps round the house - whistles after dark
You've no call for running out till the house-dogs bark.
Trusty's here, and Pincher's here, and see how dumb they lie
They don't fret to follow when the Gentlemen go by !
'If You do as you've been told, 'likely there's a chance,
You'll be give a dainty doll, all the way from France,
With a cap of Valenciennes, and a velvet hood -
A present from the Gentlemen, along 'o being good!