That feels a bit like the "I have nothing to hide argument." Should we just accept that probably spammers no longer send address verifying emails, and tacitly approve this change helping them out if they do? Ultimately, the default should be to let people decide for themselves to opt in to something like this. Forcing this with some pretty big head scratching holes in the benefits seems rather evil.

Looking at the preference, it isn't auto loading images in 'suspicious' messages (the help text more or less says this).

So trusted messages are now leaking read receipts.