The reference to thargoid or guardian items is all a part of whats known as ua bombing but can be done with any corrosive alien items and leads to various station services being unavailable aka partial station shutdown. And its counter is providing Meta-Alloys...
That aside, the first question regarding Lockdown for me would be, are you wanting to cause it or prevent it?
Then as for prevention or bringing it out, yes the best way is to spend a lot, mostly in handing in bounties, carto data helps too, but bounties are usually quicker and also according to all info gathered regarding lockdown is the recommended method. But the bottom line is when your security forces or other innocent npc's are being killed your security rises and your INF drops and fast, the basic counter concept is to raise the INF and keep security from changing which is done by doing things that raise INF, usually the fastest way to do this is missions and bounties and carto data.
That said, currently when handing in missions you will get notifications from the faction as to what effect it has, so here you are actually getting hints that people are causing your system grief or not. And depending on whats really going on you might get several kinds of notifications, about you are helping to prevent us from going into famine, or civil unrest, or lockdown, or outbreak, or bust...You can easily test this by handing in a donate mission, or any other type of mission. If you don't do this when you have suspicions then you will find out the hard way by waiting for the tick and then seeing the effects results...
You can also see hints of what may be going on by the mission types that are being offered, if they are asking for various food types, famine may be closing in, medicines wanted, outbreak is closing in. Things like this occur before a state becomes pending and they happen because other players are doing detrimental things in your system.
As for causing Lockdown, yes, easy enough to do, the higher the population is the harder it is to do, but killing security does it the fastest..a bit harder now as well with the new fast response units sent when such crimes are going on. They are very powerful ships that can take your shields off-line without firing a shot, so beware of that if you are planning to cause lockdown.
This thread has a very helpful chart for causes and counters...and much more..
https://siriusinc.enjin.com/home/m/35379595/viewthread/29164127-background-simulator-tldr
This thread has more very useful charts and other useful info
https://forums.frontier.co.uk/showthread.php/193064-A-Guide-to-Minor-Factions-and-the-Background-Sim
The only thing missing from both is recent changes, some are really bad, others are near irrelevant and most notably missing from any threads I have seen is info regarding Anarchy systems, Anarchy factions, Anarchy stations....for that I have created my own research and am glad I did. The only real note about it in these is that they are the opposite of non anarchy...which is only partially true.