I don’t believe those pages have the unique class/id structure that custom pages do to let you only impact one specific page, but my bigger question is probably what is the underlying goal of hiding it?

I am also looking for this possibillity. We use enrollment link from external web pages, and invoicing is also triggered from the same external page when a user klicks on the enrollment link.

The share link button makes it a bit to easy to bypass the invoicing.