Zwenze, those people can still roleplay 'good' characters outwardly. But internally, their souls now have a black spot on them, and we (Settings) own them. If they are called on to do something in the future (in an event or quest), they will have to obey.. or suffer the consequences.
As a fictional example, if you did a lot of quests to enter the fictional Super Secret Assassin's Guild Area just to get that cool Assassin's Cloak (fictional as well), and made promises to NPCs along the way, we reserve the right to call in those marks. If that means if you are called on to do a certain thing, such as 'donate' 50,000 tria to the leaders of the Assassins, you MUST do it, or be punished.
I am not saying refusal to do as told will end up with your character being given to True Death (character deletion). But, then again... I am not saying it won't.
Watch your step when you walk the darker paths. It may come back to bite you.