strunk convinced banks that they should allow customers to overdraw their accounts and charge them a fee to do it. what you saw 20 years ago... >> right. >> bergman: ...was that people were writing checks. if they bounced, they would often have to pay more than one fee to the bank? >> oh, absolutely. >> bergman: plus to the retailer. >> plus late fees. so, i'm saving them the $30 or $40 merchant fee and the late fees and let alone the embarrassment of it. you know, it's not a nice thing to go home to your wife and tell her that, "well, they bounced my check." >> bergman: and strunk took it a step further by convincing clients to make the checking accounts "free" to entice more customers. but was it really free? >> sure. no service charge, no nothing. no maintenance fees, nothing. there was no charge whatsoever on the account. >> bergman: except overdraft fees. >> that's not in the fee schedule. that's a separate fee. >> bergman: but is that what, in the end, would pay for the free checking? >> yes. >> bergman: the fees from that? >> it would. the two best marketing words in the unite