To block access to a specific website across all managed guest sessions, you need to add the site to the"list of blocked URLs". This ensures that regardless of the session type, users cannot access the specified site.

Verified Answer from Official Source:

The correct answer is verified from theGoogle ChromeOS Managed Guest Session Guide, which explains that adding URLs to the blocked list restricts access across all sessions.

"To enforce web filtering policies during Managed Guest Sessions, add the URL to the blocked list in the Admin console under User & Browser Settings."

By configuring the blocked URL list, you enforce consistent access policies even when devices are used in guest mode.

Objectives:

Implement web filtering for Managed Guest Sessions.

Enforce consistent security policies across sessions.