That does not remotely sound like the behaviour of responsible "email publishers". Responsible behaviour is to only email people who asked for it, and to stop when they tell you to stop. Clever trickery to spy on people is not the behaviour of responsible people.
If their intention was as you say, it would be really stupid and unreliable trickery, not just because some systems might load the images without the user reading the email, but also because the user might read the email without loading the images. And even if they were to only and reliably load on reading, reading the email does not in any way imply that the user wants to receive it. Lots of people open email before throwing it away. Some mail readers show a preview which may be enough to read the message. Does that count as reading or not?
No responsible organisation would rely on this kind of trickery, and no organisation that relies on this can be considered responsible in their handling of email.
