[zamadatix]

Or rather have the browser treat the no-network session period with private window logic where the session is deleted if the no-network browsing session ends or dies (e.g. incognito puts a virtual session data container in RAM). That would even allow the app data (prior to triggering the mode) to stay cached without risking side channels with future resource loads.

[pattyj]

The whole premise was to return to the pre-web 2.0 days but have the option for a user to enable modern web app capabilities. Which your idea would be a step towards.