Earlier, they have been using a custom client to fly and climb walls on Infection. This isn't even the sad part, some of them are staff on Minetime. If you didn't know Noobcrew owns that server aswell. This is a disgrace that they come here to do this kind of stuff when they know hacks aren't allowed. Luckily, @Veracity_ was willing to come look at the problem, he banned some of them but not all of them. They're probably around the gamemodes causing alot of issues.
The best thing to do is to tell the staff that They Can't do this, even though, they probably already know. This is sad to be honest.