Text watermarks are possible - one previously-used method is to use different ascii characters for spaces and dashes, that looks invisible to the user but can b

Text watermarks are possible - one previously-used method is to use different ascii characters for spaces and dashes, that looks invisible to the user but can be detected if it’s a straight copy-paste (even when printed due to slightly differing lengths). Of course it’s possible to process these out, same as an image watermark.