You must be joking! What Arnett did was basically act as a pawn for Saddam! No real damage ....apart from showing himself to be easily susceptible to manipulation from the Iraqis!
What Geraldo did on the other hand is draw, on live TV, current US military positions AND THEN say, with etching on the sand, where the troops would move to in the following hours and what strategy they would follow! That would have easily cost some of those troops their lives, especially when you consider it was live TV and there was a big chance Iraqi generals were watching.
Geraldo, by far, made the bigger error. Through his STUPIDITY he put US lives in jeopardy. Arnett on the other hand just proved he is shifty.
Anyways I lost all respect for Geraldo after the Afghan fiascos where he showed his wrecked thought patterns. For one he carried a gun, and boasted how he would use it (the significance of that is it put other journalists, who are normally not actively shot at, in danger of being viable targets. Remember in most campaigns journalists who die are usually the victims of 'passive' causes like stray bullets, landmines, and other events that are not specifically targeted at them. However armed journalists pretending to be GI Joe can put all in the role of armed combatant).
However the main thing in afghanistan which put me off Geraldo was the whole 'bullets are flying all around me' when the nearest conflict was miles away! That showed him to be unprofessional and petty.
Anyways what geraldo did, even if it was a mistake, was worse than what Arnett did, even if Arnett meant every word.