On 03/06/2014 10:04, Joseph Wright wrote:
> I can see how one might set up a 'preset if not already set' approach,
> but I'm not sure how it's different from simply starting off with a
> default.

yes true but probably in the usual case where each key setting happens
in a local group, and only happens once in that group then any kind of 
is probably equivalent to just setting the defaults initially at the 
outer level.
(Apart from side effects like writing to log, or global increments that 
the order or number of times, the key has been set)