Have any of those you are considering hiring ever betrayed their former employers?

Case in point: The Thunderbolts (Marvel Comics) or The Avengers' "Hawkeye" (also Marvel Comics)

Many a team has met its downfall due to some idiot who thinks he's above the law. You probably don't want men, like "Wolverine" or "Gambit", that can't take orders, or guys like "Citizen V" or "Hawkeye" that are already in trouble with the law. Like it or not, one stray can ruin the rep of your entire organiztion.