Prop keys 

A second set of keys that can be left on top of a desk to give the impression that you are in the office (versus on a long lunch or having left early) but just not at your desk. An extra cell phone or --in the case of military personnel--a beret or other headgear--can to be used in a similar fashion.

Boss: "Bill, can't have gone far...his keys are on his desk."
Uncool Coworker: "That's true, unless those are prop keys."

Prop keys by surlygirl63 October 8, 2011