Was browsing videos off YouTube, when I stumbled upon the
APB Enforcers Intro video, which inspired some ideas. The Enforcer faction of the game are essentially vigilantes given legal sanction by the government of the game's city, a desperate move to deal with the ever-growing problem of criminal activity.
Now, what does this have to do with Shadowrun, you ask? Let's assume Governor Brakhaven decides to step up the fight against criminal activity in Seattle, by actively recruiting Enforcers right out of the Shadow community. The City Security Act basically offers amnesty for past crimes to applicants, and grants them the same legal enforcement powers given to officers of Knight Errant.
This doesn't mean a CSA-approved Enforcer can't run the Shadows of course, or that he has to be a shining paragon of virtue. He just has to be careful to keep his Illegal Activities under wraps, or at least to keep the right people interested in protecting him. And you can always make connections with different Law-Enforcement groups. Just because Knight Errant is Seattle's official Police Force doesn't mean you can't instead make friends with Lone Star. ...Or perhaps you prefer to make a deal with the Yakuza, to "overlook" certain activities in exchange for "favors"?