At some point in high school I stopped standing. I want to say my freshman year but I could be wrong. It was just on a whim one day, although I was a bit of a rebel at heart, I was not the type of student to get in trouble for anything.
Anyway, from the day I first decided to ignore the pledge, I was never reprimanded for it. Some teachers would stare daggers at me but I never received any punishment nor were my parents notified.
Edit to add: The time period would have been sometime from 2007-2010