The next day I went to the Bose store, and they immediately replaced it with a new one - no questions asked. I think Bose must have realized just how flimsy the original cord was, because the new one I received has noticeably thicker shielding (not by much, but noticeable) and the mini-jack end is a different design that looks like a standard 90-degree plug as opposed to the old end that was pretty small and was about 120 degrees.
I did notice that the sound coming through the new cord was quieter than with the original. In my opinion the sound quality is just as good if not better, and I wasn't listening to anything really loudly anyway. I just noticed that I now have my iPod volume set consistently higher with the new cord.
Anyway, just wanted to let everyone know that Bose has updated the cord for the QC15. And who knows, you might be able to bring in a perfectly functioning one and get it replaced, if you think you need to. Wouldn't hurt to try if you don't like the original design.
All in all it is a greaat product despite this.
If your volume is lower, keep in mind there is a Hi/Lo switch on the cable end that plugs into the headphones. See if that's set to Lo?
If you happen to bust your cord of your own fault, they are only $15 to replace OEM