Here The Queen - Queen's Guard - and Soldiers can put anyone (but the Queen) in jail!
Anyone in jail can NOT post anywhere else!
This can be used as punishment and you can let them out in time - or you can leave them here with no food and let them rot. That - or you can leave them here - but take food from the food hall (post - taking food for .... in the Food Hall forum) and then post here (Giving prisoner food) then they have been given food for the next 3 days - but also are still stuck here!
That or put them in jail for a bit - get bored - you can publicly kill them in the The City! Just let me know you are doing so - I'll give you the get go - and then they'll be out of the game!