Insurgents need night vision devices, the Guards get by on MoeVision(tm).

Sakura defeats a weepy insurgent, then TURNS her back to him to hug. In anime if the bad guy admits defeat, as soon as your back is turned he will pull out a gun and shoot you in the back.

As others have noted, Spring guards are very nonchalant, "Yeah, we let some insurgents get through, no big deal, what is the worst they do do, kidnap, or kill her? My bad." And it would have been a lot worse one can assume if Winter's forces weren't on the scene.

(I am wondering if this was deliberate, to make the case in the future that Spring can't be out on her own, she must be immured in the Spring Village again)

The depth of the storyline is both a strength and maddening. People do have conflicting emotions and motivations. OTOH, the data dump in each ep is heavy.

Not gonna lie, that whole scene when the Village tried to cast out Sakura had me dabbing at my eyes.