I have since some days a cheat detection installed. It sends me warnings about people trying to use all kings of tricks to kill or mine faster, and all kinds of other stuff.
I observed the results for a few days and talked to a couple of users that showed up on the alerts. Some of the users admitted to using some form of cheat, such as a gamer mouse that clicks faster than normal. Most however said that they do not use that or do not even know what a hacked client was. Interestingly, ALL of those that said they had no idea, stopped showing up on the alerts – magically as it seems.
So I want to give now a warning to all users that I will be enforcing bans on such cheating. So you better get a vanilla client and switch off the speed features on your mouse or it’s been the longest time you have been on the server.