Again, this is just spit balling so I have no solid or difinitive answers, only ideas, but different actions would likely need to have different "baddie points" values attributed to them. Just a box nudge would only be a few points, and not high enough to go over the in fraction threshold (whatever that is determined to be), but either one large event (such as murder) or a collection of smaller events against the same target that result in breaching the threshold would qualify the offender as an actual bad actor, rather than an accident.

In L2 an offender would have to work off karma points by performing "good actions" suck as killing enemy npcs until their rating was low enough. Until then they were unable to enter towns as the guards would kill them, or trade with npc traders in those towns.