I'm tempted to throw in something about "honor among thieves," but I'm trying to cut the cliches from my diet in the new year.
Still, I'd never realized how contentious a phrase that whole "who watches the watchmen" thing is till I was looking up the original Latin of it. It comes from Juvenal's Sixth Satire, y'see, and not only is it referring in context to how you can't lock your wives and daughters up to keep them virtuous 'cause they'll just seduce whatever guards you set on them, but the passage itself might not actually be something Juvenal wrote back in the first century A.D. Where's Alan Moore when we need him?
Sixty-One - Standard Operating Procedures