Hi,
You can give smc-stop password.
Edit..
To password-protect the client
1. In the console, click Clients.
2. Under View Clients, select the group for which you want to set up password protection.
3. On the Policies tab, Policies and Settings, click General Settings.
4. Click Security Settings.
5. On the Security Settings tab, choose any of the following check boxes:
*Require a password to open the client user interface
*Require a password to stop the client service.
*require a password to import or export a policy
*require a password to uninstall the Client