Invalid email addresses cause performance problems in large JIRA instances

There are some standard email addresses that are intended to be ignored. RFC 2606 (http://tools.ietf.org/html/rfc2606) lists .example, .invalid etc.
At the moment JIRA tries to send email to these addresses 10 times before giving up. This is an extra, unnecessary load of the outgoing mail thread.

A valid use case for such email addresses is service or headless accounts. A JIRA user is created so that a remote system can log in and create issues. As the reporter of the issue that user account is sent email. But no-one ever wants to read email for a service account!

An alternative would be to allow JIRA users to not specify an email account, or flag the account as a service account.