These guy have been banned for hacking in other servers. I have proof of one that sometimes plays in your server. Please take a look as I screenshot it at the time it happened. If they are legit no problem.
These guys tend to come in and attempt to run the server like its there own. Not all of them. Some are cool. But there are a few if you don't go by what they want and let them farm they get there way however they see fit.