There are several reason for us banning an account. In general we ban accounts which violated our ToS. So make sure you didn't do anything wrong. (our ToS) Most reasons for banning someone are the following:
In most cases we ban users who are showing NSFW content without being in NSFW mode. But first we try to contact the streamer via chat to turn NSFW mode on. So make sure to check your chat regularly!
Another reason can be, if a streamer is gaming without gaming mode activated. Likewise we try to contact the streamer first.
Of course users who stream copyright infringing material, harass and spam are being banned without a trial.