Viconia will leave if your rep reaches 18 (I believe). There's a patch that will prevent party members from leaving you because of rep reasons, at
http://members.rogers.com/mrkevvy/
As for getting mugged by the Law when you have a rep of 1: I love it! That's just as it should be! I would expect the shops to close, the guards to come after me, wanted posters all over the place. What I don't see, and what I wish was in place, was an underground of malcontents who would contact you and provide services, including items and quests. That's the way things function (in a sense) in reality, and the way they function, as well, in Arcanum.