The Most Useless Electronic Program

The past month or so I've been getting a lot of mail in my box that isn't for me. Is for other people in the neighborhood. First class mail with sensitive financial information (I can tell based on who it's from and how it's marked). I put it back in the box with the address circled and write "delivered to wrong address". I figure the people it goes to should know how their mail is being handled. I know it's got to be just a carrier issue, but I've been hearing about it happen on forums online more often lately, seems odd. If they track every piece of mail and know where it is at any time, it doesn't make any difference if the carrier is going to screw up at the end.