The lion cannot protect himself from traps, and the fox cannot defend himself from wolves. One must therefore be a fox to recognize traps, and a lion to frighten wolves.
Active, open, and energetic opposition to your PMO's goals is something of a rarity. The widespread acceptance and acknowledgement of the validity of project management techniques makes such opposition a risky proposition. But over-the-top resistance, which I'll call a frontal assault, does occur, and the PMO professional must be prepared to overcome it.
Think of resistance to project management implementation as coming from three potential sources: