Here's the thing, though.
As a user, if I start getting your mailing list emails because someone else decided to sign me up and there was no confirmation, I'm going to mark it as spam.
As a user, if I start getting your mailing list emails because someone else decided to sign me up and there was no confirmation, I'm going to mark it as spam.
It always amazes me the business that make unsubscribing difficult. That is the real way to get placed in spam.
I don't care if the unsubscribe links works or not, I already have a faster path.
Depending on your email provider if you mark it as spam that could also be known by the sender if your provider supports the complaint feedback loop.
Here are the docs to see what info is available when sending through mailgun.
https://documentation.mailgun.com/en/latest/api-events.html#...