Why? Tell me? Your team has less point than the other team for 3 seconds? Noobs in your team? You need to go to the toilet? Leave at the very last seconds when your team is about to win so that your other team mates will get more crowns?
People who leaves in the middle of a LD game will make team unbalanced, increase the team with less players' percentage of losing, creates unfairness. YES! I know the team who has less players will get more crowns if they won...but.... They won't win. Grrrrrr.... WOOF WOOF! Grrrr.....