object banned would be dm fodder, any skill, any spell, any weapon in the inventory of that object would be impossible to use. (this should only be used sparingly - to turn off spells or skills entirely, and fix the arena).
this bit is actually relatively sane to consider doing....
this bit is harder.
object illegal would be for local government, they would define the law in each town. So if the town had a spell comet in its illegal ob, then it would be illegal to cast comet in the town. If cast, it would still take effect, but there would be a crime item added to the inventory of the player who cast it.
Anyone on the same map would get an evidence item, if they took damage, the evidence would be stronger (item level would be higher), if they were killed, then the evidence would be about as strong as it was possible to get.
Also, whenever a crime occurs, each player gets a low level evidence item for every other player on the map, how high level that is compared to the others would need to roll against intelligence. Likewise our felon will try to cover his tracks, and will himself generate evidence /against/ everyone else on the map, this based on an Int&Wis roll (shifting the blame).
If a player were to go to the city hall then and 'report' all evidence items that they have would be transfered to the region constable, and combined. Other things would contain evidence too, the squares that the crime occured on would hold evidence, everytime someone walked on them though, the evidence value (level) would fall, and eveidence for the passing player would be added. Al evidence items would have a food value too (players forget, footprints wash away...)
The death messages then would map to post-mortem evidence, I am not sure how to make these inconclusive, maybe they shouldn't be.
After collecting all this evidence then, the constable could chose to bring to court against one of the people there is evidence for. There can be a court (this is already being implemented by someone else) that could choose to convict or not.
Note all the references to misleading evidence, it would be quite possible to get a false conviction, especially if not all the players reported the crime.
In effect then, dms would act merely as internal affairs and secret police (like america's FBI) - complaints about the constables would go to them.
Atm there are probably enough people on MF to make this a real possibility, at least for scorn and maybe navar. Other servers are too small, so they would merely have the banned inventory for now.
Another point, to make something illegal, the government would have to get a copy of it - to ban spiderweb they would need a book of spiderweb, to ban stealing they would need a scroll of stealing. By placing these in a special room in city hall, then these items (books, scrolls, etc) could be opened and their contents placed in the illegal ob. this would require fact-finding missons
