Some people™ would consider it a usability bug.
If one does not want to be bothered by KWallet authentication requests, simply set no KWallet password and KWallet will silently open in the background when needed.
If I have no password set, anyone with physical/root access can open it, even if I'm not logged in, right?
If I have a password set but it is the same as my login passwort an attacker would need me to be logged in.
The problem is: I first type my password in the login manager and then immediately after that korganizer requests the kwallet passwort to sync the google calendar. Or maybe networkmanager needs the password for the wireless lan.
Gnome/gdm can do it. KDE can't. There were some patches floating around somewhere doing something with pam but nobody bothered to implement it in kwallet directly because ksecrets/ksecretservice would be replacing kwallet anyway.