Company policy is I get a weekend at home every three weeks. That's the only time I use my keys, so most of the time I just leave them in my suitcase anyway. I don't even think of taking them out until I have to unlock something. If I do get locked out, there are 5 other people who live in my house.
Of course, people in m house don't freak out, grab a shotgun, and barricade the door when I knock, either.