Where I grew up the Pledge was absolutely a mandatory part of every school day, and was said before morning announcements through the loudspeaker. Every room had a flag in it, so students in that room could Pledge to it. I grew up in an urban area, so my experiences are skewed urban. I couldn't imagine an individual teacher having a choice in the matter.

Of course, as I posted in the parent, the Supreme Court allows for individual students to stay seated and not salute the flag if they choose.