I went to make a screenshot. I am new to this, so I opened up a board, and in doing so, someone accepted. All I wanted to do was make a screenshot so I could redesign Shogi (Japanese Chess) pieces.

Another reason would be if you started up 4 or 5 games, and then 2 accepted. You might want to concentrate on those 2 games. Why make 4 or 5 in the first place? Because you don't know who would be interested. Instead of waiting for 1 person to accept in one kind of game, you sent out multiple invites and see who bites. Then you play. In that case, it would be useful to cancel a game. Even if a person didn't use this option the right way as mentioned before, they can still do it. If all they want to do is mess with the system, why would they care if the system credited them with a loss? They are just messing with the system. People in my case and the second example I outlined would have that loss carry with them when it really shouldn't.