They just tried that here, but not for 6 months more like 6 days, and i am pretty sure it have not helped one bit.
I have been driving in the left lane only for many years, but i was also way past the speed limit all the time, so only even larger idiots had to flash me to move over. ( once the queen and her just dead husband )
They and the following car with security people passed me fast and i was doing 130 on a motorway that in the 90ties had a 110 km/h limit all places ( now 130 )
my argument why people can drive where they please if the keep the speed up are.
If everyone drive like now ( speed limit at least ) and then keep right, no one could legally overtake them, and so we would have empty Left lanes and congested right lanes. ( most Danish roads are just 2 lanes in each direction )
And i just read that since 2010 traffic on the Danish roads have gone up with 31 %, so cutting one lane off all multi lane roads seem stupid to me.
But of course if the right lane are congested and slow moving than you could pass, but Danes dont mind driving 130 km/h 10 feet behind another car, and they might slow down to 110 in thick fog.
But one congested lane, and slow moving on fast roads, i see as more problematic than the occasional lane hogger, that should move over if people could bother to flash them.
It is pretty damn rare you encounter another motorist that do 5 km/h slower than the limit, far more rare than you see people doing 5 km/h or more over the speed limit.
So i say drive where you please. but for god sake move right if you are one of the few slow guys.
What i would prefer to see is the police out there busting all those guys for whom the speed limit are not enough. those guys are the ones making the biggest problems in the fast lane, and i am sure the most verbal ones in telling other people to move right or out of their way as they are thinking.
i have yet to feature a case of left lane hoggin in my youtube uploads.