The Lord of the Rings: The Two Towers
Eowyn is a noblewoman looking out over the kingdom when the flag flys away from the long post. While viewers might have thought this was a preplanned metaphor or heavy-handed symbolism, it was actually just a mistake of the wind and poor attachment. Since it obviously fits perfectly with the tone of the scene, editors had to keep it in the final cut. Thankfully, Miranda Otto didn't break character.
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