They used to do this with maps - eg. fake islands - to pick up when they were copied.

And what purpose would this serve, exactly?

while I think this is a fun idea -- we are in such a dystopian timeline that I fear you will end up being prosecuted under a digital equivalent of various laws like "why did you attack the intruder instead of fleeing" or "you can't simply remove a squatter because its your house, therefore you get an assault charge."

A kind of "they found this code, therefore you have a duty not to poison their model as they take it." Meanwhile if I scrape a website and discover data I'm not supposed to see (e.g. bank details being publicly visible) then I will go to jail for pointing it out. :(