It seems the vast majority of drama we've heard regarding guild banks comes from ninja schemes and disgruntled members. Vaela of Hyjal expressed her exasperation with guild banks in the Guild Relations forum. She feels that there is an imbalance between players who donate resources to the guild bank and those who make the most withdrawals. The original poster asked for suggestions on systems to fairly distribute guild bank resources.
The responses focused on cooperation and reciprocity with the guild bank. The purpose of the guild bank is to fun the guild's activities and exchange objects of value. In the end, the system comes off as a communist type of public ownership arrangement, as opposed to the free trade system that rules the auction house. To quote Karl Marx, "from each according to his ability, to each according to his need." Communism as we've known it has largely failed, most likely because people don't fully buy into the system.