Haha I know they don't check in on you and vise versa. The post says it was tracking... ? I assume maybe she went through customs or something to get out so they have record of her leaving without her bags? Or maybe she was supposed to collect her bags and didn't know, so they flagged them? I really have no idea. The post is here if you wanted to check it out: http://answers.yahoo.com/question/in...2110006AA91SFw
It's the "best answer" post.
I've heard so many stories of people leaving that I figured this isn't a common occurrence, but I'm a worrier so I thought I'd still throw it in the thread so you can all ease my mind. :P

As for my carry-on, I always use a small backpack so I will just take it with me.