Should I check the box?
If you share a computer and are concerned that other people might impersonate your identity, you should not check the "Remember my credentials" box. In this case, if you select the "Logout" link or close your browser, you will prompted for a valid User ID and Password when you next access the system.
How does it work?
By checking the "Remember my credentials" box, you allow the the system to place a persistent cookie on your local computer. This information will remain in your web browser's cookie cache even if all of your browser windows are closed.
How can I make the system "Forget my credentials"?
You can force a credentials prompt (re-logon) by clicking the "Logout" link on the navigation menu. The next time you logon, you will again be asked to choose whether or not to allow the system to "Remember my credentials".