If they wanted to watermark (I always felt it is irresponsible not to, if someone wants to circumvent it that's on them) - they could use strategically placed whitespace characters like zero-width spaces, maybe spelling something out in Morse code the way genius.com did to catch google crawling lyric (I believe in that case it was left and right handed aposterofes)
Just replace them with a single "-" or a double "--". That's what many people do in casual writing, even if there are prescriptive theories of grammar that call this incorrect.