For any given mechanism, if it has different behavior between an ephemeral session and a regular, persistent one, it should trigger the warning bar. Browser caching with distant Expires is definitely one of those. In this case, disallowing the persistence would make all the retrieved resources instead have session-length cache expiry.
Think of the full effect of the warning bar + "Disallow" button as going back and pretending you had opened the page in an Incognito/Private Browsing mode tab from the start--and then making that also happen automatically for any further pages from that domain. It session-isolates caching, cookies, and basically any other form of persistence except explicit bookmarking.
For any given mechanism, if it has different behavior between an ephemeral session and a regular, persistent one, it should trigger the warning bar. Browser caching with distant Expires is definitely one of those. In this case, disallowing the persistence would make all the retrieved resources instead have session-length cache expiry.
Think of the full effect of the warning bar + "Disallow" button as going back and pretending you had opened the page in an Incognito/Private Browsing mode tab from the start--and then making that also happen automatically for any further pages from that domain. It session-isolates caching, cookies, and basically any other form of persistence except explicit bookmarking.