Quote from Markillion
The signs at spawn clearly say Banable and Jailiable.
Also the first 2 signs you see in the cells area warn you that you will be trapped if you enter a cell that isn't yours :3
must have missed those signs... there are a lot of signs in the cells area though.
but a lot of people are from what i can tell are thinking being jailed is like a warning, which leads to a ban next time.