Earlier quoted context omitted.
I "know" that. I'm asking how does Google differentiate between a transactional and a non transactional email? They also say in their guidelines > *Marketing messages and subscribed messages* must support one-click unsubscribe, and include a clearly visible unsubscribe link in the message body. So how is Google determining what is a Marketing/Subscribed message? If they're not, then am I required to tack on this head…
If you’re sending transactional emails like password resets or MFA, then the emails will have close to a 100% open rate. This is (likely) an important factor that Google uses to judge whether email is transactional, or more generally whether it is desired by recipients, alongside other factors like having a very low complaint rate.
So I can disable a competitor’s email functionality by triggering a whole bunch of password reset requests for all discoverable usernames?