user7271,
Welcome to bj21!
Casinos with the "database participant" notation in CBJN are known (or strongly suspected) of exchanging information about "undesirable patrons" with other casinos. The database can be local or national, and can be free or by subscription. The information consists of name, alias, photo, license plate number, SSN, known associates, AP or cheating methods, etc.
Hope this helps!
Dog Hand