You can already do this with a robots.txt file
This malicious solution aligns with incentives (or, disincentives) of the parasitic actors, and might be practically more effective.
> If your web page is blocked with a robots.txt file, its URL can still appear in search results, but the search result will not have a description.
https://developers.google.com/search/docs/crawling-indexing/...
So, a robots.txt will not keep your site off of google, it just prevents it from getting crawled. (But, to be fair, this tool probably does not do this as well)