Your profile does not show what version you are running, I thought it was the OSE, sorry.
AFAIK, there's currently no way to stop a user from using the iSync connector or Outlook Connector beside not giving them access to the connector (to download and setup) : there's no such checkbox in the CoS tabs (while there's one for Mobile, POP3 and IMAP4).
There's a RFE in the bugzilla :
Bug 20513 - Create COS for standard user vs professional user.