I was sure he was going to die through the whole game. Even when he was cleared of all charges, I wondered if more would be brought up somehow.
I knew where the end of the game was because Telltale always have final puzzles like that - the only exception I can think of right now is Abe Lincoln Must Die - and when LeChuck showed up, I paused the game and wondered in the notes I was taking whether LeChuck was going to turn out to be evil and kill Guybrush and fulfil the title.
So I guess I wasn't really taken by surprise. Though that wasn't an execution. More murder.