Replying to an earlier post

Maybe I’m out of the loop, but how would I watermark a text without sounding obvious? By using weird phrases? They get edited. By using e.g. an exact combination of starting letters over a large paragraph? One changed word and it’s broken. And even if not, I could happen to write the same myself, and then?

How am I hiding a signature in Plain text? Anyone got a better idea than my silly ones?