CAS - What is the "Warn me before logging me into other sites" checkbox?

This feature is for those who may require extra assurance about the privacy or security of the data they enter online while using a web site participating in the Central Authentication Service (CAS) single-signon service.

When you log into CAS, you have the option of being warned each time CAS tries to log you into a new application or service. This option raises awareness about what might otherwise be silent authentication events. For example, this enables the visitor to a web program to be alerted to the fact that an authentication step was performed while accessing the web site. This helps the visitor to remember to confirm that the correct identity credentials are being used by the web site before entering any security- or privacy-sensitive data.