I live in a very rural area. It's not that odd to have a gun ready when you answer an unexpected knock at the door. There are all kinds of problems with opportunistic meth cookers, armed thieves, arsonists, and the odd home invasion robbery-rape-murder when Democrats come calling. A 911 call will get the deputies to show up to count bodies a half-hour after the shit goes down, and half the places have no cell shot so even making the call means fetching the phone first.
So yeah, it's prudent, not paranoid, out here. People don't normally display a gun, but there's an even chance the homeowner is packing or has some kind of weapon in jumping range.