Banned means they are not allowed back on the site. And this happens because of a breaking of the rules. Either purposefully, such as trolling. Or coming to promote beliefs that are not Christian or anti-Christian, foul language, inappropriate comments, threats, bad pictures, personal attacks, links to bad sites, soliciting, etc..
Or a person habitually breaks rule that could be overlooked if it were not so common. Such as we can all get upset and saying things we shouldn't. But if you consistently do this.
And it doesn't matter if you mention names, we can all see the 'banned' under their name. And since you brought up 'fraud' I'm assuming you mean Buckets and/or Alexis. The story is that both girls were the same adult male, and that is the reason for the ban.