You can speak with the fief owner through teamspeak before trading. You can also get information about the environment if there are bandits etc. Its important to speak with the fief owner before trading because many clans has closed borders, which means they will attack anyone from the outside of the clan or ally. There are also no rules about attacking, anyone is free to attack anyone they want.
Probably you've been kicked out of a fief by the owner due to Supply&Demand concerns. For example we Mercs, kick out "factionless" players or players from opposing factions out of our fiefs in the northern part of out territories, but we allow everyone to trade in southern part (Dhirim area) as far as I know Druzhina also allows factionless players to trade in the desert area. Still, they cannot speak for the actions of the other players, which means you can get attacked by the other factionless players in the free trading areas. Unless you are a member of an allying faction which means the friendly faction will protect you in the area.
It all depends on your diplomacy and sometimes thickness of your pocket. Don't go into an area without talking with a clan leader or trading officer. Calradia is an hostile environment.
Check diplomacy section for border policies.
http://forum.meleegaming.com/diplomacy/