The follow up autoresponders are scheduled to send as soon as the participant registers. Unpublishing the event will not prevent them from being sent. The follow up autoresponders should be disabled in order to prevent them from sending.
  1. Navigate to Fundraising > select TeamRaiser
  2. Find your TeamRaiser and click Edit
  3. Click Manage Autoresponders
  4. Click Disable next to each follow up autoresponder