At MrGenerations request Moving this to a feature request.
I have seen ticketing systems implement email flood protection by using exponential backoff, e.g. if a customer submits $NUMBER of tickets in $TIME then flood protection will reject further tickets for $WAIT_PERIOD.
More advanced solutions will increase $WAIT_PERIOD according to an exponential scale (or Fibonacci sequence) if flood protection is triggered again within $WAIT_PEROIOD+$TIME.
This is how Zendesk does it for example: About mail loops and Zendesk email – Zendesk help