It's both, to be fair. The freezing has made things worse, but only because there were already cracks and potholes for the water to fill and then freeze in.
I do worry that the cops will now get a lot of spurious calls by local busybodies about people who are in fact driving sensibly on a legal right of way though. It would also have been good to see the BBC point out that 4x4 groups do take part in enforcement days, although considering their editorial leanings I'm not too surprised that they didn't mention it...