Re: driver's license--I took a look at the Iowa laws. Driving without a valid driver's license is a misdemeanor.
On the other hand, driving with a valid driver's license that just doesn't happen to be in your possession is an 'infraction'--the worst that can happen is a fine, and there was a strong implication that you had a good chance of getting off with nothing.
Consider that her mother's place is about a mile, driving on quiet streets. And she's a pretty girl who may have already had experience to show her that big eyes and an apologetic voice can get you out of traffic tickets.
That's a roundabout way of saying that I agree.