I've actually had something similar happen to me whilst doing inferno cow runs in private games. The thought had never even crossed my mind that someone would be scrolling through the list of games and attempting to guess the passwords. The guy that joined my game sent me a party request and got irate when I didn't respond instantly. I don't get offended easily so I just shrugged it off and started using a more complex password. You really have to wonder what people like that are hoping to accomplish. All I can figure is that they are looking for people to steal from. It may seem like stupid video game drama but we really should ban people who do shady stuff like this. It leaves a bad taste in your mouth and can drive away new players.