With rare exceptions, if they don't have guns, they often lack skill at arms, not to mention stored food, water, and other supplies to get through the incident. Recently, I have been picking up budget guns when they cross my path. My limit is $100 so I have only accumulated two used single shot shotguns and one 22 rifle. In an Allison or Ike type of event, I am prepared to lend certain neighbors a budget gun and a box of ammo. If necessary, I can throw in a bag of white rice and a bag of pinto beans. 
However, in a longer term scenario, I won't be lending anything. If they want to buy or barter for a gun, or rice and beans, the price is going to be a lot higher than now, when the grocery and sporting goods stores are open.