Are you concerned of your mailbox's security?

Isnt it funny why my bank sent me a new replacement credit card when the one i received from them a few weeks back hasnt even been used? I have this habit of taking a peek at our locking mailbox each time i'm on the way out. If there's any mail inside, i'll take it along with me and read it inside the car. They did not specify anything in their mail at all. But instinct tells me that my old card's security has been compromised and they detected it though i've not even used it.

But i think the bank shouldnt have sent me the new replacement card by regular mail. What if i dont have one of those security mailboxes installed at my house? Someone might just walk past and go through my mailbox. You wont know what those morons are thinking of, right. Thank god i have a locking mailbox. Now i've got to destroy the first card and use the one i receive instead. Gosh, i have so many credit cards. How to keep track of them all?