Try it. The various MSPs I use report to within a minute whether I open an email or not, and they do this effectively on Gmail and other clients as well. I see

Try it. The various MSPs I use report to within a minute whether I open an email or not, and they do this effectively on Gmail and other clients as well. I see no way they could do this besides the tracking pixels they embed in email, which means that google does not prefetch, but I'd be happy to be proven wrong.