I don't really mien this

Is Latin really a cloak of secrecy?

<digression theme="The wonders of spell-checkers">
I originally spelt that cloac, and the spell-checker helpfully suggested that I might have meant cloaca. :-)
</digression>

Diane James is said to have written vi coactus after her signature, indicating that she was signing under duress:

The document formally notifying the Electoral Commission that Ms James had taken the Ukip helm was submitted on Monday with the phrase “Vi coactus” after her name, meaning “under duress”. The term is used in the belief that it invalidates signatures on legal papers. 

More here

I don't see how this works. If it's widely known what the Latin tag means ...

<digression>
...especially among the public-school educated ... 

<meta-digression>
(and for non-British readers, and maybe some  British ones who make the naive assumption that words mean what they say] I should clarify that this is the reverse of what you think unless you  know better – a "public" school, by a historical accident, is not at all public [in particular, it's not in public ownership]; it is public only to the extent that it is open to all – "like the doors of the Ritz", as some disputed quotee once famously said)
</meta-digression>

... people like Dulwich College alumnus Nigel Farrage
</digression>

... what is the point of using it as a coded message? Maybe it was a double-bluff: surely a grammar school girl and student of "tourism with languages" like Diane James would have known that if the phrase meant that she was under duress it should have been vi coacta. In that case there are three possible conclusions:

1. Ms James meant that some other (male) person was under duress.
2. Someone else wrote it in after she had signed, and simply made a mistake.
3. Ms James was making a deliberate mistake to indicate, secretly, that she wasn't acting under duress (although she wanted to give the impression – to witnesses of the event – that she was. Too clever by three quarters)

My brain hurts. Anyway she's gone. And squabbles and niggles and scuffles and ... and all other sorts of mayhem with the ending "-<double-consonant>le" have broken out. The name Strassbourg Oaths, known to me because of a seminal document in the history of French (discussed here and in many other places in this blog) now takes on a new reference – the language that presumably  preceded the alleged shenanigans.

b

PS – a clue:
Turn winch and have a good chat. (7)