Well, what is a player supposed to do, then? Stuff like "Lockdown is a function of the system state" is not really telling me anything. What and how is player action influencing states?
I don't understand your question?
It's not a function of 'system state' (that's not a thing?), it's a function of security status, which is shown in the status screen in system.
Things which would've caused lockdown now reduce security status... things which would remove lockdown or civil unrest now increase security status.
Security status itself is a slider going from, lowest to highest, Lockdown, Civil Unrest, None, Civil Liberty.
Things which increase security include handing in bounty vouchers, trading weapons and completing relevant missions/ scenarios.
Things which decrease it are violent crime, smuggling weapons, and relevant missions/ scenarios.
FD don't put information out there about these things because it's not meant to be front-of-mind for people playing. That not being the case is a bit of a design flaw...
So... "what's a player supposed to do?"... answer is nothing, since it's not meant to be front of mind. But, you can play and observe what happens, or intuit (e.g bounty hunting sounds like the right thing to do to fight a lockdown, right?)