The 'Walk The Line' app, created by Marvellous, uses the iPhone's accelerometer to determine whether the user has had one too many. It will be promoted amongst festival-goers throughout the summer.
Walking in a straight line earns the iPhone owner an invite to Grolsch bars located a festivals across Europe, while failing the test prompts a suggestion that the user slug back a glass of water.
Warnings on the app advise consumers that the app is not an actual sobriety test, more of a way to 'bring the matter to their attention without sounding pedantic'.
The company launched the app weekend at the North Sea Jazz Festival in the Netherlands with the backing of field marketing throughout the event.
Grolsch has recruited Marvellous to create an international version of the app, which will be launched on July 20.
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