You may not want to acknowledge this, but if one is a sitting Governor, they cannot just drop completely off of the map! Especially if they have Presidentail aspirations.
The very least he should have done is to let the Lt Gov know where he was going.
I know I cannot do this in my job, and there is no reason to think the people of his state should think otherwise.
Let's get real here. The Governor is not like the President. He doesn't have the nuclear football and must be available at a moment's notice. Sanford was hours away from SC. He could easily respond to any emergencies. All governors travel around the US and overseas.