I've almost taken a gun into the post office before after forgetting it was in my pocket. I carry a 1911 OWB and that's a tough one to forget, but the Sig P238 that I usually carry in my pocket can get overlooked when I'm disarming when I'm going Postal (errr, shipping packages). I can understand it happening to others too with the number of very light, yet capable, pocket guns we have available.