myth preservation

Last Sunday evening, we rolled out to embark on one of our northern Virginia Christmas traditions: The Festival of Lights. The park service throws up a bunch of lights that cars can drive through. It's kind of neat. Not sure if it's twenty dollars' (and, at times, a long wait in line) worth of neat every year, but tradition's tradition, right?
Or, as Zoe of Baby Blues would say: Maybe tradition is French for boredom.
Regardless ...

We had the Christmas tunes a'crankin', OF COURSE, and as a particular one started up, Matt said to Lizzy: "Oh! Listen to this one! It's pretty funny. You'd probably like it."
I groaned, recognizing the early strains of the song.
So Matt turns it up, just in time to hear, "You may say there's no such thing as Santa, but as for me and Grandma, we believe."
"Huh?" says Lizzy. Or something like it. And, "What's wrong, Mom? You don't like the song?" as I groaned some more.
"Uhh, never mind," said Matt, as we skipped on to the next song.

So, you ask. When DO we tell Lizzy "the truth"? Uh, ummm, errrrr, I don't know. But not this year, I guess.