Since I now was able to re-enable minecarts I went through the outstanding tickets that concerned the signs. There was one open since March, where a user notified me that there is a feature called “eject at” that allowed users to teleport them to any coordinate on the map. Of course this is not in the spirit of the server.
Because the permission system for the minecart signs is not really convenient to manage, I had trouble disabling those earlier. I found out now how this works, but this disabled the creation of ALL signs. There does not seem to be a permission that disables the usage of existing signs. I have to figure out a nice way how to manage the plugins permissions.
I know several people have abused this feature in the past. The issue is that I cannot disable already existing signs. If you have any of them, please take them down. So please be aware that if I catch anyone with those signs, it’s a ban.