But surely it’s possible to use methods other than what currently seems to be the first and only solution: “your account has been banned, bye”. For example, if

But surely it’s possible to use methods other than what currently seems to be the first and only solution: “your account has been banned, bye”. For example, if an automated system thinks an account is sending spam, enforcing a (very low) outgoing email rate limit would be a much more reasonable first step.