I found 2 related bugs, both which are about guest permissions. First of all, guests were allowed to build in other people’s lot if they were made a member of that lot. This is changed now, and people who have friends on the server still have to first pass the settler test before they can build – anywhere.
On top of that we had a very smart guy with the username of “systemAdmin” show up here and immediately asked for someone to “op” him. While I consider such a username a poor, childish prank and a rather humorous attempt at causing problems, I let him stay online to see how this would develop. And of course, as expected, the user gave me a real reason to ban him just a couple of minutes later when he abused the possibility to pick up a couple of dozen eggs in the city and create a large number of chicken running around, which made me ban him.
This event also caused me to investigate our permission system and now it is changed so that the only item you are allowed to have in your inventory, drop, pickup or use is a wooden sword. The advantage behind that is you are also not able to die from mob damage or fall damage anymore. It should be safer to get to your lot. The only damage that you can take is lava & fire damage to prevent this protection to make people explore the nether too much. So I also restricted the starter kit to a sword and took the other wooden tools away. Sadly, but true, if you do not lock up EVERYTHING a guest can do, there will be the one or other who abuses it.