Curfew laws are in place to keep the "wrong" kids off the streets. Also, an officer can't make a stop simply because they think the driver is too young to be out. If they pull her over for, say, speeding, and look at her license to discover she is too young, THEN she may be issued that citation. If she explains, however, that she doesn't live in that town (her DL should confirm that) and that she is merely driving through to get home, such a citation will usually not be written, and if it is can be easily have thrown out.