Ok.
*As long* as your (or anyone etc) actions don't impede the progress of others at all (and you may be as you would gain right_of_ way over those still queuing, slowing them up, once on the roundabout etc) then yes, it would be fair. ;-)Similar to those leaving a motorway as a tailback is forming to then to re-join it and force their way back in (often only a few cars ahead). Or those going down the outside of a queue trying to exit a main road and again, forcing their way back in (forcing the queuing drivers back).
I saw a lorry straddling both lanes of a dual carriageway approaching a lane closure (he was doing so to prevent people overtaking the long queue of people waiting patiently in the left (open) lane) and a car mount the grass on the central reservation to get past and then force his way into the queue, right up against the cones.
Well, whilst it's true it's potentially 'safer' than turning left from the right hand lane, it does increase the traffic 'on' the roundabout and maybe therefore increase the general level of risk (granted, probably not by much).
I wonder if those who do this sort of thing all the time would be as confident when trying to jump a queue at a nightclub or cinema?
I will often use a local 'rat run' but have to do so at reduced speed (speed ramps) and the route is a straight alternative route to my destination. 1) I'm not *just* taking it to save distance over a longer trip, in fact it's the route I would have taken every time, prior the addition of the speed ramps and 2) it isn't impacting on anyone else (including the local residence as I'm having to travel at the 'traffic calming speed', as per the traffic speed calming measures that were put in to distract the racers). I only take it when I can see the queue on the main road is extended and I would save time (and traffic load) overall.
Don't get me wrong, I'll not wait when someone is dithering about, I'll try to make 'good progress' at all times but also try to do so without making matters worse for anyone else.
Cheers, T i m