I totally agree, bandits and other hostile NPCs like psychopaths and soldiers that actually attack you would add a whole new level of immersion and challenge to Trumbull Valley.
Survivors could be kidnapped from your own home or rescued from hostile enclaves, supplies could be stolen and facilities could be damaged in raids. You could even be a bandit yourself if you wanted to.
I imagine it would be difficult to implement though, seeing as it is currently impossible to attack other survivors but I'd still like to see somebody give it a go.

Yup, exactly!