That's just it, people can debit your account with nothing more than the routing number and account number. They can present a fake check with your info to a seller, and it will wind its way through the entire ACH pipeline, ending with a credit in the fraudster's account, and a debit in yours.

Hopefully, you will notice it in a timely manner and get your debit reversed. Without action on your part, the fraudulent transaction will most likely never be questioned.