They weren't rubbing enough to hear - the wheel would go around about once before stopping. Besides, she'd just brought it in to the shop (for it's "30-day free checkup" from when she bought it... except that it had been ten years!!) ... my favorite LBS, I'm embarrassed to say, but at least I can say that it had been adjusted out to the end, so my guess is it was one of their new guys who didn't know what to do when you've adjusted as far as it can go and didn't want to ask (I know, I just know my guru wouldn't have let it out of the shop knowingly ... he'd have given it new cable or whatever!)
There aren't too many things that only drag the wheel when you're riding - then it would be something in the pedal crank perhaps. I am completely unmechanical - I even suggested that smaller tires might make the brakes not rub before I looked at them and of course realized it's not the tires they hit... doh... (her hubby seemed to be leaning *hard* towards getting her a new bike, so here's hoping their trip in for gear turns into something even nicer!)