With my normal carry pistol, I would never leave home with the holster and no gun, since I always put the the holster on with the pistol in the holster. IWB tuckable holster, with shirt tucked in. Really not any other way to do this type.
If I happen to carry the 1911 OWB, I could see where it would be possible to leave the pistol at the house and walk around with an empty leather holster, but I guess after realizing it there isn't any point in having the holster without the gun, so I would probably take it off.
I guess if I ever catch myself in that situation I will know the feeling.