You said this: There are only 3 outcomes: raiders defeated, raiders subjugate the community, raiders move on.
Unfortunately, there is a 4th option that you might not have thought of… and more unfortunately, it is the worst of all 4 options…
The first three outcomes are dependent on pitched engagements. You win bad guys lose. Bad guys win, you lose. Bad guys choose not to fight and move on.
4th option is that the bad guys hang around and harass you and yours. Bleed you slow. There is no way you can stay alert 24/7. Someone will fall asleep, sometime. Maybe they snipe you every once in awhile – just enough to keep you on edge. Lack of sleep will make you irritable, then slow witted, and then you start making mistakes. All the bad guys will need after a couple weeks of harassing you is a dark, stormy night and that will be all she wrote. Nobody willingly goes out into a pounding thunderstorm except bad guys and crazy people like me… it’s the perfect time. No pitched battles to lose, either. And harassment can be accomplished risking minimum of people while your main force is husbanded or resting comfortably elsewhere.
Just saying you need to start thinking like a bad guy and less like you… (who is not a bad guy…). If you can think of it, then so can they.
The wicked flee when none pursueth..." - Proverbs 28:1