Getting knowledge in the present isn't getting knowledge from the present.
A journal, for instance, written 70 years ago by a young girl hiding from the Gestapo, isn't knowledge from the present--it was written at the time, in the words of the time, about something that was happening at the time. It's knowledge of the past, from the past.
Unless I'm pulling the journal 70 years into it's own future so I can read it, then the journal and it's encoded information has already taken the long road, when I read it in some present, at that moment, the contents of the journal is being transcoded into a pattern of reflected photons and then transcoded into neural impulses by my visual and neural wetwear. The knowledge can be thought of as being about the past, but it is inherently being acquired in and from the present. Divination via "The image of death" stuff works the same way. Same thing for actual security cameras, they recorded events as they happened and brought those recordings forward the long way. There are plenty of ways to divine already existing recordings of past events. In fact, you can accses already existing recordings of future events via oracles, if the oracle is willing. But sometimes the only recordings of some events are some combination of peoples minds and taking the photonic road out of the solar system. The first has third law issues, the second has arcane link and scale issues. In these cases, direct viewing of events is all thats left. Now, what happens if someone at the event had their own detection spells going for scrying or was sensitive to chronomancy? With the various ways of looking at a pre-existing recording, there is no risk of ex post facto detection; the transcription was detectable and detected, or not, at the time of the events. With direct viewing via chronomantic divination, while not in the normal sense going against the flow of time, you are entangling (or finding to be entangled) a past point in the stream with your current point, and while this will almost always go unnoticed, there seems to be danger in this interaction.
In other words, my position is that chronomantic divination of the past, while not directly violating the 6th law, is inherently stepping very very close to it, with the knowledge of how to step over being implicit but not necessarily the knowledge of where the line is.
Edit: I say this while playing a character whose mind-state spent two years living in an oracular array (implemented as a recursively precognitive bio-ectoplasmic processing matrix computing self inclusive sums across it's future states) of his own construction; whose doppelganger constructed a surveillance network from augmented and mind-linked seagulls. There are other ways.
Edit2: The corollary to butterfly effect with (divinitory) chronomancy is the predestination loop, which may be seen as a preexisting eddy in the flow of time. Breaking the eddy may in effect be a 6th law violation even if the eddy itself is seen as the 6th law violation by observing wardens.
