Mark,
You may also wish to try out the new --check-roundabout-flares option which checks that roundabout flare roads are sane (oneway, point in the right directions and don't extend further than they need to).
Thanks, I think I will try to outsource the job in the Finnish community, possibly by posting a note or link on my map download page http://www.polkupyoraily.net/osm/.
In the end, I fixed all (or most) warnings myself. I also ended up fixing some nearby problems. For example in Pori, most residential roads were unconnected in the junctions. Just lines arranged in a grid, but with no junctions. :-( The funniest warning that I fixed was a tiny roundabout of highway=track next to a highway=secondary or so. I replaced it with a single junction node of highway=mini_roundabout and also replaced the highway=track with highway=cycleway, cycleway=track. I wonder why I did not get any warnings for the flare roads of my nearest roundabout: http://www.openstreetmap.org/browse/way/9498558 In the map extracts that mkgmap has processed so far, each of the four Y-shaped ways that connect to the roundabout were defined as two ways, a slash-shaped way that connected to the angled way. None of the ways carried a oneway attribute. I have now split the Y into three ways and defined oneway=yes on the V ways. Best regards, Marko