As per our Master Subscription Agreement, if you delete Spanning Backup from your Google Apps domain, your backups will be queued for deletion. Or in the more formal language of Section 12.5 the agreement: Upon the effective date of termination, We shall have no obligation to maintain or provide any of Your Data and shall [...]
Updated 10-Apr-2012 It was fun while it lasted, but the “3 Seats Free” program has been discontinued. You can now start a free, fully-functional 14-day trial of Spanning Backup for up to 100 users in your domain. Just visit Spanning Backup on the Google Apps Marketplace and click “Add it now”.