So Samoa Air will let a few kilos slide, but the airline is unlikely to provide a refund if passengers roll up to the tarmac with a lighter load.

CNN: Pay-as-you-weigh airfares the 'next step'

Perhaps Wall Street will slide slowly downwards, letting air gently out of the bubble.

ECONOMIST: Trapped by the bubble

When its infantrymen meet resistance, they either slide round it or call in the air force or the artillery.

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