It's usually a surprise when someone pulls out a hip flask and offers us a swig, although in many situations we would probably be more grateful than startled.
In a crowded airport with stratospheric bar prices, it would surely come as a welcome gesture, as it would in many similar 'dry' situations where alcohol is unavailable.
The sight of a hip flask brings back memories of the USA's prohibition era, when no right-minded person left home without one in his or her pocket. And today neither does any grouse moor enthusiast or follower of drag hunts.
So what is the chosen tipple? Overwhelmingly whisky or brandy, with gin and vodka running a close second.
Hip flask use has national considerations, and in countries with strict licensing laws it is obviously more common than in places like Spain, where a drink can always be obtained around the clock.
But who habitually carries a hip flask today? Surprisingly, and probably the last person you would think of - Victoria Beckham. She puts hers to untypical use by filling it with good red wine, as she has a self-confessed aversion to any wine costing less than 12 euros.
As owner of a Napa Valley vineyard, she and husband David enjoy splashing out. To celebrate their last wedding anniversary in Paris, the star was Chateau Lafite Rothschild 1990. Not hip flask material, but it is good to know that the tradition is alive and well, and there are hundreds of different styles of hip flask selling on the internet, from engraved crystal to pure silver.
Indeed, a habit that should be kept alive.