I was playing singles with a friend the other day. I hit a shot close to her baseline, and she pointed "out" with her finger to indicate a bad shot. Then she hit the ball, and it landed in my court (not a big winner, just landed on my side). Of course seeing her "out" gesture I thought my ball was out and stopped playing before she hit it; didn't even try to play the ball. We were playing on clay, so I asked her if she was sure the ball was out. She said, "oh no, actually your ball was in so I played it." I thought we should replay the point, but she said it was her point, as she had made a legal shot. I countered that even if she didn't yell the word "out" - she had made the standard "out" gesture. She admitted that she had initially meant "out" but changed her mind at the last second. I gave her the point, to avoid an argument. But I still think we should we have replayed the point.