Suppose that X, who used to publish RPG material licensed under the OGL v 1.0a and citing a WotC-copyright SRD in its section 15 statement. Now X publishes a RPG in a way that does not conform to the OGL v 1.0a requirements (eg it no longer includes a copy of the OGL v 1.0a together with appropriate OGC, Product Identity and Section 15 notices).
And finally, suppose that WotC commences legal action against X, arguing an infringement of WotC's copyright. It seems that they may not have too much difficulty showing a causal link between X's new publication, and WotC's copyright SRD.
I should add: I'm quoting Wikipedia, not a judge; and a single-judge decision in a British court will probably not carry much weight in argument in a US court.
But now I add further: you've prompted me to go to the report. It can be found here: Temple Island Collections Ltd v New English Teas Ltd & Anor  EWPCC 1 (12 January 2012)
And here are the relevant passages, based on my quick skim:
40. . . . The defendants do not really have a case of independent design at all. It is not in dispute that Mr Houghton had access to the claimant's work at all material times and that he participated in the creation of the defendants' work in issue in this case. The defendants' work was "for the most part created at his request by Sphere" [paragraph 14(4) of the Defence]. It was created using the photographs Mr Houghton had taken and the iStockphoto image. What is clear is that there is an issue about the extent of the defendants' knowledge of the other publicly available works relied on. . . .
55 On the question of copying, I find that the common elements between the defendants' work and the claimant's work are causally related. In other words, they have been copied. There are two points. First the evidential onus to address a point like that is on the defendants here given the obvious similarities between the claimant's and defendants' work and the undoubted access of the defendants to the claimant's work. Mr Houghton did not refer to any particular element and assert that it came from a source independent of Mr Fielder. Sphere did not give evidence at all.
56. I have referred to the obvious similarities between the works. The defendants went to considerable lengths to point up the differences between the images. They analysed the overall composition which is said to be very different both vertically and horizontally. The balance of foreground, middle ground and far ground features were analysed and said to be different in key respects. The fact the river is absent from the defendants' work was pointed out. These differences all exist but it seems to me that on the question of copying they do not help. In this case it is not a coincidence that both images show Big Ben and the Houses of Parliament in black and white with a bright red bus driving from right to left and a blank white sky. The reason the defendants' image is like that is obviously because Mr Houghton saw the claimant's work. The differences do not negative copying, on the facts of this case they have a bearing on whether a substantial part is taken . . .
57. Second Mr Houghton did not suggest he had seen any of the other similar works relied on above before seeing Mr Fielder's image. The whole point of this case is that Mr Houghton and his company wish lawfully to produce an image which does bear some resemblance to the claimant's work. The inference that I draw is that Mr Houghton sought out this other material after he had decided to produce an image similar to the claimant's. He found examples of common elements in various different places. That does not avoid a causal link. If Mr Houghton had seen Mr Fielder's image, decided he wanted to use a similar one, found the Rodriguez or Getty photographs and put one of those on his boxes of tea, there would be no question of infringement. Those images are not causally related to Mr Fielder's, they are independent works. But that is not what happened. At best the defendants used these other images to show that certain individual elements in Mr Fielder's work can also be found elsewhere. That does not make those different sources the actual origin of an element in the defendants' image. I reject the submission that the other similar works acted as a relevant independent source for the defendants.