True, but HSBC thinks you read the email, because somebody fetched the tracking pixel, right? The irony is that HSBC and others who use this kind of thing probably aren't in the least interested in when or how many times you open the email. Whoever came up with this idea (probably) really did think it was (just) a pretty good way of figuring out if they have your correct email.

They do work for the inferred purpose here though, assuming Gmail only downloads them when the email is successfully delivered to the mailbox (and thus the address is valid).

> Gmail because Google fetches them out of band. It doesn’t reveal open rates.

"Our open rates have skyrocketed! send more emails!"

Same with Apple Mail

I mean, they still work in some way. If you use tracking pixels to see if an email was read, I agree with you that this break the functionality. But if you just want to see if the email exists, then the fact that google fetches them (and triggers the parametric URL) still tells you something

What do you mean by 'fetches them out of band'?