If you're not teaching the student both flaps up, and flaps down landings, then you're doing the student a grave disservice. The student should be fully comfortable landing with any flap setting, and a variety of power settings. Initially one airspeed and one flap setting may help the student get the basics of landing the airplane...but by the time a student becomes a private pilot, the student should be entirely comfortable landing the airplane no matter what the flap setting. Flaps fail, and the student needs to be able to handle that without a second thought.