Quote Originally Posted by Assertn
Also, I find it interesting that Ace's execution seems to be more hyped up than even Roger's execution. Roger's execution didn't seem even 1/3 as secured...they didn't even use Marineford!
If i recall correctly, it was revealed Roger either let himself get caught or willingly went to marine HQ to be executed.

If he was going to die by his own will the marines probably neglected the idea that he might try to escape. Another posibility is that since it was the begining of the series Oda didn`t really thought about how strong the marines (or Roger for that matter) were and Roger`s original role was to give pirates a reason of excistence OR maybe they did had tons of defense but they were outside the island on it`s surrounding, also note Roger didn`t had a huge ass legend trying to save him