Introducing...Nothing

One-time blog skeptic, turned All-Star Questioner, Talia Friedman asks:

Can you say the Shir Ha'Maalot before benching if you do not intend to bench? 

While you might understandably think that the two are inseparable, and that there is no reason to say the introduction if it doesn't introduce anything - thus leading to the prohibition against saying Hashem's Name in vain.  This would indeed be true in other similar contexts, like saying the ברכות קריאת שמע without saying שמע itself, or the ברכה for הלל, without saying הלל.  Shir Hama'alot is different in that it is simply a chapter of תהילים that can be recited for no reason at all.  In fact, any פסוק from תנ"ך may be said, with the Shem Hashem, as long as the complete פסוק is completed.