It's near to hand, always, but not often actually on my belt while I'm indoors.
I can help someone through the storm door, get the name or phone # of the towing co. or friend they want to call.
I'd answer the door, and if they tried to force their way through the (locked) storm door I'd close the inner door & yell at them to leave.
If they persist, call police & hold the gun ready Just In Case. Heaven forbid they get through the inner locked door, 'cause I'd have a mess to clean up, and it'd all be on the 911 tape.