I'd say it's dancing around the mind magic laws... Also since the one guy could see He Who Walks Before's mark on Harry there is the possibility they can actually communicate with Outsiders, violating another law.
Interesting point. The Seventh Law is the most tricky to deal with of them all, it's the one that can get you killed for reading the wrong book. OTOH, I doubt that actually happens very often, for various reasons.
I don't think the Sight seeing Outsider taint would count as a violation, though. That would potentially put the whole Council in violation of its own law at any given moment. But the ability to see the taint might be a channel that opens the
possibility of a violation, so I could see that as one reason the Council would want to shut down production.
Besides the fact that the stuff can easily drive weak-willed people nuts, as well.