Bull Durham - The Same Woman
When Tim Robbins calls Kevin Costner outside the bar to fight, there is a crowd of people standing behind Robbins while more people are still coming out of the bar behind Costner. In the shot of Robbins, there is a blond woman standing behind him dressed all in white. When the shot switches to Costner, the same blond dressed in white walks out the door from the bar. The time difference is only a few seconds, and I'm willing to bet nobody is that quick.