User blog comment:Otakueisama/API insecure?/@comment-106.69.122.9-20140515180959/@comment-24816414-20140515224240

Also. from what I read in this thread (http://kancolle.himeuta.net/forums/showthread.php?519-Ban-Scare-Discussion) having an old api link may be a cause of your ban. Especially if the api link is from before the last event ended.

They were talking about a bug in a past event that allowed people to sortie in the event even though it had already ended. People did this to get rewards and it seems like the bosses didn't like it. ( I don't know if this is true I read it in the thread)