No. It justs clears the session vars. If you want to kick someone out you would have to test for a session vars e.g Session("LoginName") on each page, and if it is empty then redirect them to your login page.
If you are using sessions for security then once you lose that session then the next page you go to will not allow you in, alternatively if you are using sessions for the users name (say you promted for in index.asp and display "welcome <%=session("name")%>" the whole way through the site then after two mins it will say "welcome " because the session variable will be taken out of the servers memory. get it?