Analog... just be careful you don't trip on that soap box when you get off that high horse...
The point is, it isn't her place to dispel these myths. Just as it isn't a teachers job to dispel the myth of, or encourage the truth of (depending on your point of view) God.
Besides... parents aren't lying. There is a Santa Claus and I am him. Just as every parent of every little kid out there is...