Its hard to believe, but that is RIM's concept for a carrying lanyard...nothing more, nothing less. If you open up the device, you'll see its nothing but a blank hole. Unless the tether cord is paper thin, you will not be able to close the back cover.
This design phenomenom should not surprise anyone. If you've suffered through the 11 months of the Orignal Storm, then nothing RIM does should surprise you, If it wasn't for the pushed email, they would have been buried by Android....Kaput!
Also, end of life for the Storm2 is 10/10/10. VZW has spreadsheets confirming it.