One wouldn't - but, as I've said, if the road is very quiet, then it does not really matter 'who does what', does it?
I've just come in for a warm, switched the TV on, an it's one of those traffic police shows. Driver trundling along the otherwise empty motorway, in the middle lane, traffic car pulls in behind, and gives him 3 points, plus I think was said - £100 fine. No, it doesn't inconvenience anyone, but the rule, even on an empty motorway, is to stay in L1, unless...