Re: Surely the answer is watermarking
So, with a little effort I too can run the incriminating text which may or may not have yellow feathers  through a noddy neural network before forwarding it to the leakhole of my choice? Do you have a spec. for this NN, please?
Actually, one's natural language skills should be good enough to do such refactoring, it's probably quicker and less likely subtly to alter the meaning of the message.
 Canary, as in the unfortunate birds used to warn of low oxygen/high CO levels dahn t'pit.