CiraSync is a one-way sync in terms that it will never write back to the source (GAL, Public Folder, etc). However, any changes users make to their phone contacts will propagate to their Outlooks / mailboxes. If changes are performed on CiraSync managed contacts, these changes are only temporary and will be overwritten on the next scheduled sync. So, if you delete a CiraSync contact from your smartphone, it will delete the contact on Outlook. However, in the next sync, these contacts will be restored.