As an Organizer, you can choose to receive an email each time someone signs up.
Click on the SignUp Name in My SignUps on your Dashboard:
Go to the Settings Tab>>Email Preferences
You can choose to be sent an email notification when someone signs up "Always" or "Never" The other options allow you to choose to receive an email notification is someone signs up within 1-7 days of the Spot. This last feature allows you to get notifications of just the last minute sign ups.
These emails will be sent to all Organizers listed on the SignUp's Details Tab: Tour of Details Tab