6.06c says nothing about intentional. I contend that even if you require intention, I would default to it being intentional unless I have evidence to the contrary.
I have a running argument with a good friend of mine that believes the batter needs to be able to complete his swing. I tell him I agree and I will allow him to do so if he stays in the box doing it. As you work a game take note how many times you see a batter step accross the plate with no runners on. I feel fairly certain you will see at best a 90/10 split. I think I am being generous in that number.