10 More Movie Mistakes That Became Canon

10. The Crowd Goes Mild - A Knight's Tale

Early on in A Knight's Tale, after William (Heath Ledger) wins his first battle under the guise of knight "Sir Ulrich," Geoffrey Chaucer (Paul Bettany) raises his hand in victory and sings his praises, all while the assembled masses don't react, like, at all.

Given that the crowd were hooting and hollering throughout the fight moments ago, it doesn't really make sense that they'd suddenly show no emotion whatsoever for the winner.

And that's because this is a cleverly concealed mistake. A Knight's Tale was shot entirely in Prague, Czech Republic, and so most of the extras were Czech locals without much grasp of English.

And so, when Paul Bettany was speaking his lines, most of the extras had no idea what he was saying, hence their utter lack of a reaction. 

It was only when Mark Addy, who plays their pal Roland, started cheering loudly out of nowhere that the crowd joined in with him.

Impressively, it flows totally organically in the final scene, proving how a mixture of clever editing and actors thinking on their feet can paper over a sure-fire gaffe.