Not that this is something I want to do, but I wonder if, for example, a slave (not a Dwarf, Greensking, or Skaven, don't care about the race outside of that) of the Chaos Dwarves escaped to the Empire and had managed to secretly learn Runecraft by watching the Chaos Dwarves work ... how illegal would that be on the former slaves part, from the perspective of the Karaz Ankor.
Because while it's illegal to learn the secrets of the Karaz Ankor without that permission .... he didn't gain that info from them. Like, the same thing with warmachines, if some humans back in the day had stolen knowledge of how to make Grudge Throwers by spying on the construction process that would be a crime, but if they had met the Elves with the Elves already knowing how to do that then it'd presumably be fine because they didn't steal the knowledge from the Dawi.
In this case this hypothetical character would have stolen a secret of the Karaz Ankor, but it was stolen from enemies of the Karaz Ankor, in fact they stole the secrets of the Dawi's enemies, it just so happens that they share'd said secret. So, assuming that the Dawi knew for a fact it happened this way, would they still blame this character for learning their secrets, or is it legally permissible as the secrets were learned from an independent party?
Edit: I figure that the former slave would be in the clear, but it'd be yet another Grudge against the Chaos Dwarves .... though I'm very interested in the opinions of others here.