Whatever the law, when does learning from what we read devolve into plagiarism? The poster child for this category would be those programs that generate nonsen

Whatever the law, when does learning from what we read devolve into plagiarism? The poster child for this category would be those programs that generate nonsense English text that recognizably resembles a known author. They choose the next character at random, conditionally based on the previous characters. Too short a context, and the results are gibberish. Too long a context, and the results are plagiarism.