BrE: “Don’t try and stroke the dog, in case he bites you.” “It’s better not to smoke, in case it kills you.” “Don’t run, in case you fall over.”

But not: “Don’t run, in case of falling over.”

I’ve always understood it to be true wherever English is the dominant language that “in case” usually (in ordinary, everyday language) means “against the possibility” but also (in highly formal language, i.e. officialese) means “if”. I’d like to see a reference for the claim that there’s a British/American difference going on here (I’m Australian, BTW, so more or less neutral).

Did the knowing smiles really mean, “foreigners can’t get English quite right”, or did they in fact mean, “highly formal language can be funny sometimes”?

A memorable example of the phrase “in case of fire” (actually, an ambiguous one in context now that I think about it) appears near the end of the Goodies episode “Rome Antics“. The episode can be found on Youtube in three installments (links below), and the relevant sign appears around 8:46 in the third installment.

http://www.youtube.com/watch?v=kdEiZRua0Z4
http://www.youtube.com/watch?v=4NP3OSYWCE8
http://www.youtube.com/watch?v=fFrTZQ-njmE

Well, I had to search long and hard on Google to find an instance of “Do not $x$ in case of $y$” (almost all co-locations of “do not” and “in case of” have the “in case of” first, usually followed by a comma), but finally I found one : “Do not use in case of rectal bleeding, as this may indicate serious disease.”

My interpretation of this (as a native speaker of $Br.E$) is that the author is saying “If rectal bleeding is occurring, do not use [this substance]“, rather than “Do not use [this substance] in case it leads to rectal bleeding”.

Thus I tend to agree with “ds” that the “Do not use the lift in case of fire” example is not as open to mis-interpretation by $Br.E$ speakers as Graham’s experiences in Europe have led him to believe.

My interpretation of this (as a native speaker of ) is that the author is saying “If rectal bleeding is occurring, do not use [this substance]“, rather than “Do not use [this substance] in case it leads to rectal bleeding”.

Thus I tend to agree with “ds” that the “Do not use the lift in case of fire” example is not as open to mis-interpretation by speakers as Graham’s experiences in Europe have led him to believe.

(Of course it’s possible that I’ve been corrupted by living in the US for the last 12 years, but I don’t think so in this case).