Price Set Option still publically visible when visibility set to 'Admin'
This belongs as a comment, but I'm bending the rules because I wanted to include screenshots.
I was unable to replicate this.  See my attached screenshots from a demo site.  The first screenshot is while logged in as an admin, the second is as an anonymous user on the same page.  Since you're able to replicate this on the demo server, we must be setting up the page differently.  Could you please edit your question to detail the exact steps you took to set this up?  Or perhaps link to a video?
As admin

As anonymous