Maxperson
Morkus from Orkus
Third, I disagree with the (prevailing) sentiment that you should get the player's permission to impose divine punishment on a paladin who violates his oath. That's the whole point of the oath- he has to live up to it or fall.
Not really. He has to live up to it or seek absolution. It's only for willful violations with no signs of repentance that the paladin will fall.
This paladin had no choice, so the violation wasn't even willful. It's not like he walked up to the man and hacked him down of his own volition.
I do agree with you that you don't need the player's permission, though. Or put another way, you already have the players permission by virtue of him picking a which comes with requirements and penalties.