With or without your knowledge, someone may attempt deposit funds into your checking account. Financial institutions often have stricter rules about accepting a deposit from someone who is not a signer on the account than from someone who is. This is to protect the account holder from fraud and the bank from liability.

Preparation

When someone attempts to make a deposit into your checking account, the bank requires your checking account number. This is to make sure the funds reach the proper destination, and it also can be used to verify whether the person should have access to your account.

Problems

If the person making the deposit doesn't have the checking account number for your account, it's unlikely the bank representative will look it up for him. If the representative does look up the account number, a problem arises if you have more than one checking account with your name on it. In addition, if the bank representative goes ahead with the transaction, it's possible that your full account number will be printed on the deposit slip issued to the depositor. This can expose your account to fraud if the person making the deposit doesn't have the authority to have your account number.

Bank Liability

A bank can incur liability for accepting a deposit to an account from someone who isn't a signer on your account. If someone deposits a check into your account and the check is returned for insufficient funds, the bank assesses a returned check fee to you, the account holder, not the person who made the deposit; if the person did not have your authorization to deposit the funds, the bank is liable for its actions.