This was a scam that caught my grandmother 10 years ago. The New York Times did a story on the industry:
State regulators have tried to protect victims like Mr. Guthrie. In 2005, attorneys general of 35 states urged the Federal Reserve to end the unsigned check system... But the Federal Reserve disagreed. It changed its rules to place greater responsibility on banks that first accept unsigned checks, but has permitted their continued use.
...In all, Wachovia accepted $142 million of unsigned checks from companies that made unauthorized withdrawals from thousands of accounts, federal prosecutors say. Wachovia collected millions of dollars in fees from those companies, even as it failed to act on warnings, according to records.
http://www.nytimes.com/2007/05/20/business/20tele.html
I documented my failed effort to get Washington Mutual to reverse the checks written against my grandmother's account:
Generally I recommend having two bank accounts, one which is rarely used other than for deposits and functions as a backup in the event your primary account is compromised. I also recommend not using a debit card and instead get the financial discipline to just pay off credit card balances each month and then use credit-cards for as much as you can from banks not tied to either your primary or backup checking account.
You have 30 days from receipt of your bank statement. It's in the audio interview of which this article is an exerpt.
"1. Unlimited liability applies. The standard of unlimited liability applies if unauthorized transfers appear on a periodic statement, and may apply in conjunction with the first two tiers of liability. If a periodic statement shows an unauthorized transfer made with a lost or stolen debit card, the consumer must notify the financial institution within 60 calendar days after the periodic statement was sent; otherwise, the consumer faces unlimited liability for all unauthorized transfers made after the 60-day period. The consumer's liability for unauthorized transfers before the statement is sent, and up to 60 days following, is determined based on the first two tiers of liability: up to $50 if the consumer notifies the financial institution within two business days of learning of the loss or theft of the card and up to $500 if the consumer notifies the institution after two business days of learning of the loss or theft."
That's very specific. When it comes to check fraud, I'm going to trust the guy who has spent his career working with the FBI on check fraud.
I see where you went wrong there. Have them disallow internet access to your accounts. Easy for you, easy for hacking.
If that checking account has money for your rent or credit card bills, it could be disastrous.
So I use a separate account at a separate institution for my "spending money". All I use it for is to withdraw money at ATMs.
If you want this from a developer perspective, the subject is discussed in great detail in the following blog post series.
How ACH works: A developer perspective - Part 1 => http://engineering.gusto.com/how-ach-works-a-developer-persp...
How ACH works: A developer perspective - Part 2 => http://engineering.gusto.com/how-ach-works-a-developer-persp...
How ACH works: A developer perspective - Part 3 => http://engineering.gusto.com/how-ach-works-a-developer-persp...
How ACH works: A developer perspective - Part 4 => http://engineering.gusto.com/how-ach-works-a-developer-persp...
and
HN Meta Discussion : https://news.ycombinator.com/item?id=7636066