Yep. It is perfectly possible. I bet those peasants were drunk or drugged. Something crazy has happened.
To be serious, that is very weird but I think I've seen it somewhere. Even though those peasants became militias to protect their homes but the game mechanics put them as defending units of a region. That is probably why that happened.
I've seen it numerous times. I would even go so far as to say it is quite common in times of war.
I guess the peasant militia are simply viewed as general militia (by game mechanics), and militia represent the authority of the region/realm. As they are unhappy with the situation and the current rulership, they vent their anger on the people at hand. The (general) militia. Game mechanics don't always make sense
