A lot of folks don't really know what their bank policy is until they actually get charged the fees. It is a service most people don't think they will ever use as I don't think folks start a checking account with the idea of overdrawing their balance. It is usually some sort of mistake.
I read an article recently that said 8 out of 10 of the major commercial banks have this overdraft protection "service". This is another difference between commercial banks and credit unions as the overdraft fees at CU's are typically lower to no charge if you sign up for it in advance (if you have funds in a savings account and it is linked to your checking, they will transfer the money over for no charge or you can set up a line of credit much like a credit card for overdraft protection).
Congress is looking into this, too. According to the article I read banks may be taking steps so that congress doesn't act by doing more disclosure (now there's an idea!

). Some ideas are that folks will have to agree to the fees in writing or be given the option to opt-out. Perhaps, a warning on the ATM machine and the fees that you will incur if you about to go over--much like you have to agree to the fee charged on the ATM now (if there is a transaction fee).