Tin foil hat time....
So Mark Sanford just up and disappears, doesn't tell anyone where he's going. Almost like he was kidnapped or left in an emergency.
He reappears and says he was hiking. Shortly there after he changes his story that he was visiting his mistress in Argentina, and his car was spotted parked at the airport.
So, if you were going to go to Argentina to visit your mistress, wouldn't you have told people you were going to be out of town so people wouldn't be suspicious?
It just strikes me as odd that he would disappear for days and almost immediately flip with the mistress story. I can't help but suspect there is more to this story.