Ok here's some results, this one was captured, didn't show UserId and isn't registered or unconfirmed:
HEADER
POST /forumz/login.php?do=login HTTP/1.0
Accept: */*
Cookie: tccsessionhash=e575197d38d5a7c06fe82415e7688d00; tcclastvisit=1303620326; tcclastactivity=0; vbet_sessionUsed=1
Host:
www.thecodecage.com
Pragma: no-cache
Proxy-Connection: Keep-Alive
Referer:
http://www.thecodecage.com/register.html?agreed=true
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)
ENTITY
vb_login_username: elderatot
cookieuser: 1
vb_login_password: 18gcAEp796
submit: Log in
s:
securitytoken: guest
do: login
vb_login_md5password: 8fb830d941xxxxxxxxbfe29fcc8
vb_login_md5password_utf: 8fb830d9412xxxxxxxxbfe29fcc8
ajax: 0
KEY
2b021b1f
Just in summary, i went through 1,000 (no really i did

) entries and none of them including the one above showed UserId either filled in or blank.
Hope that helps.