Platform: PC
ISP: Comcast
Type of Internet Connection: Cable
Internet Connection Speed: 30Mb/s?
Date & Time: About two months ago
Frequency: Once (did not reproduce personally, but I've heard of it happening to others)
Character Name: Uubb
Race: ElvaanM
World: Lakshmi
Main Job: THF
Support Job: WAR
Area and Coordinates: Upper Jeuno
Party or Solo: Solo
NPC Name: None
Monster Name: None
Steps:
I would rather not provide the exact steps on a public forum, but suffice to say it is possible to accidentally corrupt your FFXI install with a fairly minor amount of effort and log in to FFXI with an unpatched version of the POL client (which does not require the security token/SE ID). You need to add a check that verifies that a valid SE ID / Password (/ potential token) has been entered before allowing people to log in to the FFXI game, or this method could be used to compromise accounts. Alternatively, you could greatly reduce the odds that anyone could pull this off if you would just start providing a patched version of the POL client.

I tried to report this through the website the first time and didn't expect or receive any correspondence, but I just received word that someone had repeated it more recently so it looks like it hasn't been fixed and I am reporting it again and this time in a way that allows you to respond. Everyone that I know who has done this has done it accidentally, which means that it's easy and common enough that someone interested in it should have no problem doing it intentionally.