[Zallar]

I don't think you're going to get a statement that says "We will not punish exploiters unless we visually see it ourselves" because then everyone goes "Ah Ha, if I know the staff are asleep, I've got the quoted permission to use every exploit in the game. There are combinations of options available, Logs, Guides, etc. If they have enough internal evidence that they have a reasonable confirmation of an exploit, they'll act on it.

However, knowing this community, I don't blame them on not relying upon player supplied screenshots and logs because of the extremes people will go to doctor up evidence. They can only trust their own sources.