LEL, several riders eschewed the actual route and short-cutted by taking various faster main roads and that seemed to be accepted, . . . if anyone would care to comment why that ploy to shorten the overall distance on that event was met with approval I would be interested in reading same.
Apologies in advance to those who think this is 'off topic' but minimum distances on DIYs need to take account of the shortest reasonable route - including any shortcuts (which aren't really shortcuts: the route selected is a 'long cut').
Others have explained the freedom Audax UK allows for riders to choose their own route between controls. The freedom to choose enhances my enjoyment of long distance cycling. I confess surprise that the 'land of the free' (R USA) does not espouse this freedom though the US road network is so sparse that alternative routes which perhaps offer more climb for less distance, or more distance for less climb, or main road or minor road options (than the routesheet suggestion) are normally non-existent.
But here the road network in most parts of the UK is such as to enable choice. I know many will just load up the 'issued' gpx and follow it. But I (and I assume/expect) others check and decide to take off routesheet choices for a variety of reasons which include:
1) Shorter or less climb
2) less navigational challenge (eg at night)
3) Use of narrow (ie single carriageway with hedges, gravel, potholes and poor viz) roads - are these more 'dangerous' than main roads(?)
4) Use of main roads - wish to avoid during rush hours (for example)
5) Use of main roads - less busy at known times of the day
6) Shelter from the wind (eg valley route v ridge route)
6) Exposure to a tail wind (eg ridge route v valley route)
7) Audax is less bold unless there's a bit of off road (including cycle paths) - try to include it on every ride.
Organiser's route has to be described 'reasonably' on a text routesheet. Sometimes a better route is too difficult/risky to so describe - too great a risk of riders getting lost.
9) Visiting friends or points of interest off route.
Freedom to choose and navigate a route is a skill that I thoroughly enjoy exercising (NB from a long orienteering background) and following the route is equally difficult to following the route suggested by the routesheet. Finding alternatives and assessing their merits is part of my preparation for a long ride. Entirely content for others to just follow the routesheet or follow the pink line on their gpx-loaded GPS. In fact if I'm riding with others (at the time) I have a decision to make: stick with the group (with its attendant benefits) or divert on the alternative I have determined is 'better'. Sometimes I choose the former: sometimes the latter. In fact it's more fun to divert from others riding at one's pace and see whether the route one thought was better was faster or slower.
Finally I'm always conscious when I strike out 'off route' on a calendar or perm event, that the organiser has risk assessed the recommended route and not the variation I'm taking. On a DIY this is not an issue.