Out of the blue - an unexpected death

If, having passed the several notices which warn of danger, someone sets out to climb, by means of steep, rock-cut steps on the side of a vertical cliff, steps which are uneven, which slope haphazardly and are frequently slippery as a result of guano or seaweed, and they then slip and fall to their death on the rocks below, it is, by its nature, an accident, and accidents are unpreventable.  

At least by the presence of otherwise benign group members.

And no matter how tragic, due to the youth of the victim – only twenty-four, the brevity of their marriage – just eleven days, an accident is an accident.

Except when it is not.

Except when it was not so much preventable but deliberately executed.

And not just heat-of-the-moment deliberate but planned in advance, the time and place selected, and the killer hired.   Because although, in this case, a killer might not have been thought necessary, that the obvious suspect was elsewhere at the time, although not very far elsewhere, it was useful to have witnesses who would testify, with complete honesty that what they had seen was an unpreventable accident.

[This direction for the plot occured to me in the less than a minute it took me to walk upstairs, having finished my lunch - the victim hitherto unsuspected - funny indeed this writing lark!]