Actually, in guard systems, and systems owned by players, like Omi 100, I can kill a trader without warning and the trader can't do anything about it.
edit- but ofcourse I don't, I ask them to leave and if they don't I kill them, I don't care about how much money they have or what they're carrying.
edit 2- and yeah, killing on sight in 100 makes sence because the Order would want it's secrets kept away from public eyes and anyone who sees what we're up to can't be kept alive, too risky for us.