Yeah, I wonder too. Just checked the docs, they use tracking pixels. So blocking images should block it 100%?

I tested it myself. You are welcome to do the same.

What platform (web, android, ios) did you test on, and how did you test? I used emailprivacytester.com on a few email services and gmail wasn't susceptible to any of the attacks.

I tested it by sending an email using ses and virtual deliverability manager to my gmail account which is configured to not load images automatically. Then I observed how the open is registered in the virtual deliverability manager’s dashboard.