Hipopotofobia that can already be done, through basic permissions.
A cool idea for a prison plugin, would be to break the typical prison mold.
Example: Prison is a pretty solitary mode, people don't tend to play with friends unless server specifically add additional things for groups to do, e.g. control a prison yard (outpost), or gang headquarters (cells, etc.).
A feature that would work nicely would be something along the lines of, when mining with members of your gang, you can get certain buffs, and if you are too far spread from your gang, you get nerfed a bit, so like you mine faster in groups, you get extra potion duration in pvp, you can "smuggle" (sell) items faster or for a greater price.
