Wherever I go in Europe, I seem to see signs outside lifts that say “Do not use the lift in case of fire”. Inevitably, one of the British people standing waiting for the lift to arrive then says “We shouldn’t use this lift, because it might catch fire”. Knowing smiles are exchanged, meaning “Foreigners can’t get English quite right, can they?”
This is another example of the ‘same language false friends’ that I wrote about in another post. In US English, there is nothing wrong with the sentence, where “in case” means “if”, so the whole sentence means “Do not use the lift if there is a fire”. In British English, however, “in case” means “against the possibility”: “Do not use the lift because there may be a fire”.
The British English warning should read “In the event of fire, do not use the lift”.