The Wisconsin Office of Privacy Protection says bank, credit card and credit union offers may make you vulnerable to theft and fraud

Are you getting blank checks in the mail from your existing credit companies? The checks, a marketing tool for credit companies are called convenience checks and are mailed to consumers everyday. The checks are intended to make it easy for you, the consumer to pay off other bills or access cash quickly. The convenience checks probably have your actual account and/or routing numbers, making fraud incredibly easy. They come in your mailbox and can make you vulnerable to theft and fraud if your mail is intercepted.
The Wisconsin Office of Privacy Protection says that if you do not want to receive any in your mailbox, opt-out of marketing offers by following these simple steps. Call your existing bank, credit union or card issuer and ask them to opt you out of all marketing offers, including convenience checks. While you're at it, ask them to refrain from increasing the limit you can borrow unless you request it and sending you an upgraded card, i.e. from gold to platinum.. All of these marketing strategies may make you vulnerable or at best give you more material to shred.
Probably the best time to opt out is when you open a new account. The next time you have a few minutes, grab your credit cards, turn them over and call customer service. (Same thing with your bank statements.) Ask them to remove you from all marketing lists—including for any “affiliates.” They may ask you to put your request in writing. They have 120 days to comply with written requests. Oh, and if you ever order additional or replacement cards or accounts, make sure you opt-out again.
Additionally, you can opt-out of pre-approved credit offers that you do not have an existing relationship with at (888)567-8688 or online at www.optoutprescreen.com.