That's true. But also trackers (especially big ones) deliberately try to make it as easy as possible to accidentally include them in your page. e.g: the if you use their cdn for fonts/style sheets, if you include a fb like button etc.
So I think it's still concerning that once they're in, they start crawling. Although not very surprising I have to say... That's their business after all.
Yeah, of course they'll try that. They're businesses, they make their money by tracking people. When I inherit a team of project these CDN links are the second thing to get removed / fixed (after their the inevitable unencrypted passwords / homerolled security and homerolled SQL).
A friend of mine covers this more extensively in this blog post which I found a very interesting read: https://remusao.github.io/posts/static-comments.html
So I think it's still concerning that once they're in, they start crawling. Although not very surprising I have to say... That's their business after all.