> rather than blocking all external resources completely > And they do proxy all images through their own servers, so any missed trackers still get only limite

> rather than blocking all external resources completely > And they do proxy all images through their own servers, so any missed trackers still get only limited info. IMO either all external resources should be completely blocked until explicitly requested or alternatively all should be immediately fetched and cached by the server the instant it receives the email. The second option does consume more resources for the server operator but it provides significantly better privacy for users by rendering trackers completely useless.