It’s not just one email, it’s the entirety of the messages that your friends have sent to you. This is the reason why gmail keeps sending you emails, and so much more.
Gmail does not forward email forwards, and it is not required that you forward emails. The only way to see it is to forward an email forwards using your default web browser. However, once you forward an email forwards you should never forward anything else forwards to any other users.
If you forward emails, you will not get any messages sent to you. So, if someone sends you an email, you will get no emails. So, if someone sends you an email, you should not forward to anyone.
Gmail forwards email forwards by default to either Gmail’s own servers or to Gmail’s own email servers (you can also set up your own Gmail account). In either case, these servers should not forward email forwards. And if you forward email forwards, you should never forward any emails to any other users.
But… is it right to forward email forwarded from Gmails own servers or Gmail’s own email servers? Probably, but it’s not necessary. If you are forwarding email to your gmail, then you should forward the email to another user, not to Gmails own server.
The problem is that if you are forwarding the email from Gmails own servers, then those servers will forward the email to your gmail. This is an email forwarding violation that may or may not be technically detectable, depending on your setup. But if it’s not, then you are doing it wrong.
In order for you to forward it to another user, you need to be sure to be the person who sent the email. If you are forwarding a private email, then it probably means you are forwarding it to your own gmail, and not to someone else’s gmail.
If you don’t forward the email on your own gmail, then it is technically a violation of the privacy of your gmail user. The fact that this was never acknowledged in the email, that it was never asked for in the email, and that such a request was never made, leads me to believe that the sender never saw it. Which means the sender never saw your private gmail email and never opened it. Which means that you were the sender.
If you forwarded an email to someone elses gmail and they didn’t see it, then it’s a violation of their privacy. And while it’s possible that you were not sending the email to the recipient, this is also possible. If your email is sent to, say, the CEO of the company, then it’s not a violation of their privacy. But if you sent it to the CEO, then it is.
This is the case for just about every email we send out to customers, partners, employees, etc. If you forward an email to someone elses gmail, then they see it and forward it to their own gmail and never see it. This is a violation of their privacy, and is punishable by termination. If you send an email to the CEO of the company, then it is not a violation of his privacy.