I understand that in Ordnance Survey maps they would often include a small stream or lane that in fact did not exist. They could then identify any map that represented that feature as being based, not on genuine research by that manufacturer's own cartographers, but rather on simply copying from their already extant map. It's an idea that makes sense I guess, but you have to think that some hikers or explorers have been disappointed when they attempted to walk down Nowhere Lane and fill their water bottles at Lost River... only to discover that neither existed.
Similarly I understand that historians often include spurious details in their works. Say they described the colour of a diplomat or politician's tie at a famous meeting and then they will know if any other historical book describes Hitler's pink spotted tie, then that book is based not on the author's own research but that in fact he has simply re-written the other guy's research in his own. And so a lawsuit will be incoming. But again, I think, what of the curious reader who will always now believe that when Hitler met Chamberlain he was wearing a tie with bright pink spots?
A similar tactic is when you want to discover which of your colleagues is leaking to the press. Feeding different versions to different suspects and seeing which is the version emerges. A practice which reached its acme in the so-called WAGatha Christie scandal when Wayne Rooney's wife was trying to work out which of the other WAGS was leaking her, no-doubt extremely important, secrets to the bloodthirsty press which was pursuing her hotly at the time...