Smart card removal behavior
Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options
Determines what should happen when the smart card for a logged-on user is removed from the smart card reader.
The options are:
By default, No Action is specified.
If Lock Workstation is specified, then the workstation is locked when the smart card is removed allowing users to leave the area, take their smart card with them, and still maintain a protected session.
If Force Logoff is specified, then the user is automatically logged off when the smart card is removed.