I have a corporate BB8800 so it's really their phone, granted.
I had established an account password months ago so they could validate me easily when I called. Tonight I called in to extend the ring time before transfer to VM, and found my account password has been changed. I guess the master corporate IT BB phone guy can do this.
I, too, have the password issue but I did set it to the max allowable in the phone security settings (10 mins I believe). It accepts "ZXCZXC" as a 6 digit password. That's the easiest combo my eyesight and fat fingers could find.