When Nine Tails locks down a station or landing zone, will players still passively spawn there when joining the PU, or does that affect your login location?

If it is where you were set, then you stay there, yes. It does not do anything to affect you there whatsoever. That's not to say that we never will, particularly if in some distant future there's a time when they actually take over that station; that might have some ramifications for people there that aren't friendly with Nine Tails. But for now, no, you will log back in right on that station.

So there's an opportunity for some juicy game starts. Just log in casually, have a fun Persistent Universe experience, and you're in the middle of a giant PvP event.

Which has some knock-on fun potential gameplay of, I need to hire someone to come in with some big guns and rescue me. And that sounds awesome in some ways, or terrifying.