A relatively new concept to me was being employed at a Games Workshop run tournament that I chanced to witness recently. They were employing a novel rule such that any model that was unpainted had preferred enemy ruled against it.
As well as applying to unpainted models like the one pictured above, this rule was also being applied to models that had less than three colours on them. Indeed, it seems that to be classed as painted, models must have at least three obvious colours on them. I think this divisor between painted and unpainted is rather common in tournaments that I have attended in the past - I've certainly come across it multiple times in the past.
That said, I'm not too sure how I feel about the Preferred Enemy: Unpainted rule!
On the one hand, I can certain see that it would encourage players to get their miniatures painted in time for a tournament or event. But on the other hand, if that self same tournament already had composition scores associated with it, then what's the point - it just detracts from an even match up.
From a personal point of view, I actually don't mind playing against unpainted armies at all. I do prefer to play against painted ones, but that's just a preference as I'm very much in to the visual and painting aspects of the hobby, probably more so than the gaming side these days. Equally, if someone doesn't have the time to paint everything, but its all assembled and mostly WYSIWYG (or at least a sensible counts-as size at bare minimum), then I'm all good!
(Addendum: and: no -- I'm not making this stuff up just because its an April 1st posting!).