Eviebae,
Lack of ammo, lack of training with the weapons they have and lack of will to go on the offense. Who wants to be a hero?
I'd only fight when I had to. I'd most def prepare for a bug out though.
Getting infected isn't too great a worry if you're properly dressed. Shoot, you could go out in a full leather bikers outfit with helmet and bust zombie ass without worry. You might have tunnel vision with the helmet on, but it's only an example.
You just don't want to get stuck simply fighting. Stick and move.