This is a rumination on the little identifiable things that make us instantly recognize whatever it is that little thing is a part of, but which may, in their own way, be somewhat inscrutable. In this case, it's the corkscrew on the Swiss army knife.
A question to start with first. Has anyone who owns a Swiss army knife ever actually used the corkscrew to open a bottle of wine? I did, once, and have to say it doesn't work very well. It's a little too small, unless you have some super-deluxe model, and frankly the corkscrew on a decent sommelier's knife works a lot better. In part I think the fault for the Swiss model lies in it's need to fold away nice and neatly, but, really, in a survival knife, why do you need a corkscrew in the first place?
Or, for that matter, why is part of the standard issue equipment to an army - assuming the Swiss army knife, was, in fact standard army issue - a device whose sole purpose is to aid in the consumption of alcohol? Then again, they are Swiss, after all, so maybe a little wine after the field of battle was the norm.
Though when was the last time the Swiss went to war?
And yet, for it's seemingly little utility, it's on all but the smallest models, and I would go so far as to say that it would seem not only odd, but also somewhat amiss, were it not to be there in the first place.