Back when I first joined my clan, we had a pair of senior members create a little program called FUBHUB, basically the app would pull info off our servers and run it through pbbans (at least to my knowledge) and would alert you if anybody had a pbban and what it was linked by (name, ip,GUID or a combo). It also allowed you to check screenshots and view the ban in question so you could make a more informed ban.
Sadly one isn't around much and the other one hasn't been heard from for years after he got into trouble and about 2 years ago was found by pbbans staff to apparently got to the dark side which was a shame since he did so much for us.
Overal, I think I banned at least 500 people that had previous pbbans in the year or so I got to use it since we had one of the most popular BF2 Karkand servers