user(name) and EAP-TLS

Hi Folks, I'm working on securing the access to a WLAN network with WPA2-Enterprise, EAP-TLS and a FreeRADIUS server. Everything seemed to work as expected until realized that a client will be authenticated (by eap) even if the user(name), provided with the mandatory "identifier" entry in wpa_supplicant.conf, doesn't exist in the users file. To verify this I used the unedited 'default' users file provided with the FreeRADIUS package and the user/name 'FooBar'. Is that meant to be like this or do I miss something? Cheers, Klaus