Members of an activist group called "The Yes Men" scammed their way into a conference in New Orleans by pretending to be HUD officials. They refer to what they do as "identity correction":
Small-time criminals impersonate honest people in order to steal their money. Targets are ordinary folks whose ID numbers fell into the wrong hands.
Honest people impersonate big-time criminals in order to publicly humiliate them. Targets are leaders and big corporations who put profits ahead of everything else.
Here's another story about them in the New Orleans Times Picayune.