Pirates will still attack you though, and you will still have weaker defenses because the colony is so small. I feel like this will not be any less annoying. Size 3 colonies also don't make much money, so I'm not sure how worthwhile it will even be.
Sure. Although I guess friendly with pirates stop that part. If I try total core kill, I want to be friendly with pirates just to stop the raids.
However, if we still have -1/-10% pirate raids, a tier 1 battlestation and ground defenses should be enough to reliably repel pirate raids that small by itself, no patrol required. Bigger defenses are required for major factions or bigger pirate raids.
The idea is after a total core kill and friendly pirates, there will be no need for defenses or babysitting because cells bypass them or simply do not appear, and pirates do not raid if friendly. (Just eat the penalty from activity; no point removing it if it reappears the next day.) All other factions are removed from the game if their core worlds are wiped out. (I just want to explore without the babysitting, and I probably need to kill everyone, or at least kill the military worlds and let pirates decivilize everyone else.)
Size 3 colonies also don't make much money, so I'm not sure how worthwhile it will even be
The idea is to colonize tens or hundreds of worlds and make big money despite no trade income after a total core kill. (5k to 10k credits times a hundred or so instances of Pop&Inf is a big chunk of cash.) The point of the game after total core kill is to colonize the entire sector. (There is a reason why I called it the mad quest.) Enemies are generally Radiants for cores, which are stronger than everything the core worlds can throw at the player in combat.
Of course, pirates are probably the strongest faction because they have that demon power of campaign immortality and relentlessness.
P.S. Once cores start to do more than merely stick around like cursed sticky items, then that plan will fall apart.