if you overdraft your account and owe the bank money or write/cash bad checks you get blackballed by the banks and your name gets put in the chexsystems that all banks use until you pay back the bank you owe. No bank not even a credit union will allow you to open an account until you get your name removed from chexsystems. Many poor people just give up knowing they will never be able to pay off that debt and go without a bank account